Choose the best answer:

It is interesting to take __________ a new hobby such as collecting stamps or going fishing.

Choose the best answer:

Up to the present, George __________ good work in his class.

Choose the best answer:

We stopped for a rest after we __________ for two hours

Choose the best answer:

On the way home yesterday I happened__________ your sister.

Choose the best answer:

While __________ to help Tom with his math, I got impatient because he wouldn‟t pay attention to what I was saying.

Choose the best answer:

They congratulated me __________ the exams with high marks.

Choose the best answer:

Lots of houses __________ by the earthquake.

Choose the best answer:

Since their appearance, books are a precious __________ of knowledge and pleasure.

Choose the best answer:

All traffic laws _______________.

Choose the best answer:

If I had noticed him, I ___________ hello.

Choose the best answer:

_________ the way, what did you think about the movie you saw yesterday?

Choose the best answer:

 _____________ so many people been out of work as today.

Choose the best answer:

Going to the pub too often can easily become a bad __________

Choose the best answer:

Because the first pair of pants did not fit properly, he asked for _____

Choose the best answer:

My younger sister is very __________ and so she loves going out but I am much quieter and prefer to stay at home.

Choose the best answer:

_____ in UNESCO‟s World Heritage Sites in 2003, Phong Nha Ke Bang is noted for its cave and grotto systems.

Choose the best answer:

My neighbor is driving me mad! It seems that _____ it is at night, _____ he plays his music! 

Choose the best answer:

I couldn't use the pay phone __________I didn't have any coins with me.

Choose the best answer:

Tom: ''You must have had a very good time on holiday." Peter: "__________, it was a disaster. Everything went wrong."

Mark the letter A, B, C or D on your answer sheet to indicate the word that differ from the rest in the position of the main stress in each of the following questions

Mark the letter A, B, C or D on your answer sheet to indicate the word that differ from the rest in the position of the main stress in each of the following questions

Mark the letter A, B, C or D on your answer sheet to indicate the word that differ from the rest in the position of the main stress in each of the following questions

Mark the letter A, B, C or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions

Mark the letter A, B, C or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions

Mark the letter A, B, C or D on your answer sheet to indicate the word or phrase that is OPPOSITE in meaning to the underlined part in each of the following questions.

The International Organizations are going to be in a temporary way in the country.

Mark the letter A, B, C or D on your answer sheet to indicate the word or phrase that is OPPOSITE in meaning to the underlined part in each of the following questions.

Mr. Smith‟s new neighbors appear to be very friendly.

Mark the letter A, B, C or D on your answer sheet to indicate the word or phrase that is OPPOSITE in meaning to the underlined part in each of the following questions.

Humans depend on species diversity to provide food, clean air and water, and fertile soil for agriculture.

Mark the letter A, B, C or D on your answer sheet to indicate the word or phrase that is OPPOSITE in meaning to the underlined part in each of the following questions.
The goalkeeper can also be ejected for twenty seconds if a major foul is committed

Mark the letter A, B, C or D on your answer sheet to indicate the word or phrase that is OPPOSITE in meaning to the underlined part in each of the following questions.

The organization was established in 1950 in the USA.

Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction (from 30 to 34)

The Southeast Asian Games, also knowing (A) as the SEA Games, is a biennial (B) multisport event involving (C) participants from the current eleven countries of Southeast Asia. (D)

Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction (from 30 to 34)

Catherine is studying (A) law (B) at the university, (C) and so does (D) John.

Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction (from 30 to 34)

The tree that was struck by (A) lightning had been (B) the tallest of (C) the two trees we had (D) in the yard

Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction (from 30 to 34)

He has made (A) a lot of mistakes (B) in (C) his writing because (D) his carelessness

Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction (from 30 to 34)

Air pollution, together with (A) littering, are (B) causing many (C) problems in our large, (D) industrial cities today

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word for each of the blanks from 35 to 44.

WHY I DISLIKE COMPUTERS

Almost everyone says that computers are wonderful and that they are (35) ______ our lives for the better by making everything faster and more reliable, but I am not so sure that this is the (36) ________

The other day I was standing in a large department store waiting to pay for a couple of films for my camera (37) _______ the assistant announced that the computer which controlled the till (38) _______ working. I did not think this was a big problem and I (39)________ to find another counter, but of course, all the machines are part of the same system. So there we were: a shop full of customers, money at the ready, waiting to (40) _______ our purchases, but it was quite clear that none of the assistants knew what to do. They were not allowed to take our money and give to customers a written (41) ______,because the sales wouldn‟t then have been recorded on the computer system. In the end, (42) _______many other people, I left my shopping on the counter and walked out .Don't you think so that's ridiculous? It (43) ________ never have happened before computers, and that, for me, is the problem: we are beginning to depend on these machines so completely that we (44) _______ cannot manage without them anymore.

Điền vào ô 35

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word for each of the blanks from 35 to 44.

WHY I DISLIKE COMPUTERS

Almost everyone says that computers are wonderful and that they are (35) ______ our lives for the better by making everything faster and more reliable, but I am not so sure that this is the (36) ________

The other day I was standing in a large department store waiting to pay for a couple of films for my camera (37) _______ the assistant announced that the computer which controlled the till (38) _______ working. I did not think this was a big problem and I (39)________ to find another counter, but of course, all the machines are part of the same system. So there we were: a shop full of customers, money at the ready, waiting to (40) _______ our purchases, but it was quite clear that none of the assistants knew what to do. They were not allowed to take our money and give to customers a written (41) ______,because the sales wouldn‟t then have been recorded on the computer system. In the end, (42) _______many other people, I left my shopping on the counter and walked out .Don't you think so that's ridiculous? It (43) ________ never have happened before computers, and that, for me, is the problem: we are beginning to depend on these machines so completely that we (44) _______ cannot manage without them anymore.

Điền vào ô 36

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word for each of the blanks from 35 to 44.

WHY I DISLIKE COMPUTERS

Almost everyone says that computers are wonderful and that they are (35) ______ our lives for the better by making everything faster and more reliable, but I am not so sure that this is the (36) ________

The other day I was standing in a large department store waiting to pay for a couple of films for my camera (37) _______ the assistant announced that the computer which controlled the till (38) _______ working. I did not think this was a big problem and I (39)________ to find another counter, but of course, all the machines are part of the same system. So there we were: a shop full of customers, money at the ready, waiting to (40) _______ our purchases, but it was quite clear that none of the assistants knew what to do. They were not allowed to take our money and give to customers a written (41) ______,because the sales wouldn‟t then have been recorded on the computer system. In the end, (42) _______many other people, I left my shopping on the counter and walked out .Don't you think so that's ridiculous? It (43) ________ never have happened before computers, and that, for me, is the problem: we are beginning to depend on these machines so completely that we (44) _______ cannot manage without them anymore.

Điền vào ô 37

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word for each of the blanks from 35 to 44.

WHY I DISLIKE COMPUTERS

Almost everyone says that computers are wonderful and that they are (35) ______ our lives for the better by making everything faster and more reliable, but I am not so sure that this is the (36) ________

The other day I was standing in a large department store waiting to pay for a couple of films for my camera (37) _______ the assistant announced that the computer which controlled the till (38) _______ working. I did not think this was a big problem and I (39)________ to find another counter, but of course, all the machines are part of the same system. So there we were: a shop full of customers, money at the ready, waiting to (40) _______ our purchases, but it was quite clear that none of the assistants knew what to do. They were not allowed to take our money and give to customers a written (41) ______,because the sales wouldn‟t then have been recorded on the computer system. In the end, (42) _______many other people, I left my shopping on the counter and walked out .Don't you think so that's ridiculous? It (43) ________ never have happened before computers, and that, for me, is the problem: we are beginning to depend on these machines so completely that we (44) _______ cannot manage without them anymore.

Điền vào ô 38

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word for each of the blanks from 35 to 44.

WHY I DISLIKE COMPUTERS

Almost everyone says that computers are wonderful and that they are (35) ______ our lives for the better by making everything faster and more reliable, but I am not so sure that this is the (36) ________

The other day I was standing in a large department store waiting to pay for a couple of films for my camera (37) _______ the assistant announced that the computer which controlled the till (38) _______ working. I did not think this was a big problem and I (39)________ to find another counter, but of course, all the machines are part of the same system. So there we were: a shop full of customers, money at the ready, waiting to (40) _______ our purchases, but it was quite clear that none of the assistants knew what to do. They were not allowed to take our money and give to customers a written (41) ______,because the sales wouldn‟t then have been recorded on the computer system. In the end, (42) _______many other people, I left my shopping on the counter and walked out .Don't you think so that's ridiculous? It (43) ________ never have happened before computers, and that, for me, is the problem: we are beginning to depend on these machines so completely that we (44) _______ cannot manage without them anymore.

Điền vào ô 39

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word for each of the blanks from 35 to 44.

WHY I DISLIKE COMPUTERS

Almost everyone says that computers are wonderful and that they are (35) ______ our lives for the better by making everything faster and more reliable, but I am not so sure that this is the (36) ________

The other day I was standing in a large department store waiting to pay for a couple of films for my camera (37) _______ the assistant announced that the computer which controlled the till (38) _______ working. I did not think this was a big problem and I (39)________ to find another counter, but of course, all the machines are part of the same system. So there we were: a shop full of customers, money at the ready, waiting to (40) _______ our purchases, but it was quite clear that none of the assistants knew what to do. They were not allowed to take our money and give to customers a written (41) ______,because the sales wouldn‟t then have been recorded on the computer system. In the end, (42) _______many other people, I left my shopping on the counter and walked out .Don't you think so that's ridiculous? It (43) ________ never have happened before computers, and that, for me, is the problem: we are beginning to depend on these machines so completely that we (44) _______ cannot manage without them anymore.

Điền vào ô 40

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word for each of the blanks from 35 to 44.

WHY I DISLIKE COMPUTERS

Almost everyone says that computers are wonderful and that they are (35) ______ our lives for the better by making everything faster and more reliable, but I am not so sure that this is the (36) ________

The other day I was standing in a large department store waiting to pay for a couple of films for my camera (37) _______ the assistant announced that the computer which controlled the till (38) _______ working. I did not think this was a big problem and I (39)________ to find another counter, but of course, all the machines are part of the same system. So there we were: a shop full of customers, money at the ready, waiting to (40) _______ our purchases, but it was quite clear that none of the assistants knew what to do. They were not allowed to take our money and give to customers a written (41) ______,because the sales wouldn‟t then have been recorded on the computer system. In the end, (42) _______many other people, I left my shopping on the counter and walked out .Don't you think so that's ridiculous? It (43) ________ never have happened before computers, and that, for me, is the problem: we are beginning to depend on these machines so completely that we (44) _______ cannot manage without them anymore.

Điền vào ô 41

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word for each of the blanks from 35 to 44.

WHY I DISLIKE COMPUTERS

Almost everyone says that computers are wonderful and that they are (35) ______ our lives for the better by making everything faster and more reliable, but I am not so sure that this is the (36) ________

The other day I was standing in a large department store waiting to pay for a couple of films for my camera (37) _______ the assistant announced that the computer which controlled the till (38) _______ working. I did not think this was a big problem and I (39)________ to find another counter, but of course, all the machines are part of the same system. So there we were: a shop full of customers, money at the ready, waiting to (40) _______ our purchases, but it was quite clear that none of the assistants knew what to do. They were not allowed to take our money and give to customers a written (41) ______,because the sales wouldn‟t then have been recorded on the computer system. In the end, (42) _______many other people, I left my shopping on the counter and walked out .Don't you think so that's ridiculous? It (43) ________ never have happened before computers, and that, for me, is the problem: we are beginning to depend on these machines so completely that we (44) _______ cannot manage without them anymore.

Điền vào ô 42

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word for each of the blanks from 35 to 44.

WHY I DISLIKE COMPUTERS

Almost everyone says that computers are wonderful and that they are (35) ______ our lives for the better by making everything faster and more reliable, but I am not so sure that this is the (36) ________

The other day I was standing in a large department store waiting to pay for a couple of films for my camera (37) _______ the assistant announced that the computer which controlled the till (38) _______ working. I did not think this was a big problem and I (39)________ to find another counter, but of course, all the machines are part of the same system. So there we were: a shop full of customers, money at the ready, waiting to (40) _______ our purchases, but it was quite clear that none of the assistants knew what to do. They were not allowed to take our money and give to customers a written (41) ______,because the sales wouldn‟t then have been recorded on the computer system. In the end, (42) _______many other people, I left my shopping on the counter and walked out .Don't you think so that's ridiculous? It (43) ________ never have happened before computers, and that, for me, is the problem: we are beginning to depend on these machines so completely that we (44) _______ cannot manage without them anymore.

Điền vào ô 43

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word for each of the blanks from 35 to 44.

WHY I DISLIKE COMPUTERS

Almost everyone says that computers are wonderful and that they are (35) ______ our lives for the better by making everything faster and more reliable, but I am not so sure that this is the (36) ________

The other day I was standing in a large department store waiting to pay for a couple of films for my camera (37) _______ the assistant announced that the computer which controlled the till (38) _______ working. I did not think this was a big problem and I (39)________ to find another counter, but of course, all the machines are part of the same system. So there we were: a shop full of customers, money at the ready, waiting to (40) _______ our purchases, but it was quite clear that none of the assistants knew what to do. They were not allowed to take our money and give to customers a written (41) ______,because the sales wouldn‟t then have been recorded on the computer system. In the end, (42) _______many other people, I left my shopping on the counter and walked out .Don't you think so that's ridiculous? It (43) ________ never have happened before computers, and that, for me, is the problem: we are beginning to depend on these machines so completely that we (44) _______ cannot manage without them anymore.

Điền vào ô 44

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 45 to 54

In comparison with most other places in the world, family identity is rather weak in Britain, especially in England. Of course, the family unit is still the basic living arrangement for most people. But in Britain this definitely means the nuclear family. There is little sense of extended family identity, except among some racial minorities. This is reflected in the size and composition of households.

It is unusual for adults of different generations within the family to live together. The average number of people living in each household in Britain is lower than in most other European countries. The proportion of elderly people living alone is similarly high.

Significant family events such as weddings, births and funerals are not automatically accompanied by large gatherings of people. It is still common to appoint people to certain roles on such
occasions, such as „best man‟ at a wedding, or godmother and godfather when a child is born. But for most people these appointments are of sentimental significance only. They do not imply lifelong responsibility. In fact, family gatherings of any kind beyond the household unit are rare. For most people, they are confined to the Christmas period.

Even the stereotyped nuclear family of father, mother and children is becoming less common. Britain has a higher rate of divorce than anywhere else in Europe except Denmark and the proportion of children born outside marriage has risen dramatically and is also one of the highest (about a third of all births). However, these trends do not necessarily mean that the nuclear family is disappearing. Divorces have increased, but the majority of marriages in Britain (about 55%) do not break down. In addition, it is notable that about three-quarters of all births outside marriage are officially registered by both parents and more than half of the children concerned are born to parents who are living together at the time.

Today, in Britain, many couples, mostly in their twenties or thirties, live together without getting married. Only about 60% of those couples will eventually get married. 40% of children in Britain are born to these cohabiting parents. In 2000, around a quarter of unmarried people between the ages of 16 and 59 were cohabiting in Great Britain. Unmarried couples are also starting families without first being married. Before 1960, this was very unusual, but in 2001, around 23% of births in the UK were to cohabiting couples.

In Britain, the term family should usually be understood as __________

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 45 to 54

In comparison with most other places in the world, family identity is rather weak in Britain, especially in England. Of course, the family unit is still the basic living arrangement for most people. But in Britain this definitely means the nuclear family. There is little sense of extended family identity, except among some racial minorities. This is reflected in the size and composition of households.

It is unusual for adults of different generations within the family to live together. The average number of people living in each household in Britain is lower than in most other European countries. The proportion of elderly people living alone is similarly high.

Significant family events such as weddings, births and funerals are not automatically accompanied by large gatherings of people. It is still common to appoint people to certain roles on such
occasions, such as „best man‟ at a wedding, or godmother and godfather when a child is born. But for most people these appointments are of sentimental significance only. They do not imply lifelong responsibility. In fact, family gatherings of any kind beyond the household unit are rare. For most people, they are confined to the Christmas period.

Even the stereotyped nuclear family of father, mother and children is becoming less common. Britain has a higher rate of divorce than anywhere else in Europe except Denmark and the proportion of children born outside marriage has risen dramatically and is also one of the highest (about a third of all births). However, these trends do not necessarily mean that the nuclear family is disappearing. Divorces have increased, but the majority of marriages in Britain (about 55%) do not break down. In addition, it is notable that about three-quarters of all births outside marriage are officially registered by both parents and more than half of the children concerned are born to parents who are living together at the time.

Today, in Britain, many couples, mostly in their twenties or thirties, live together without getting married. Only about 60% of those couples will eventually get married. 40% of children in Britain are born to these cohabiting parents. In 2000, around a quarter of unmarried people between the ages of 16 and 59 were cohabiting in Great Britain. Unmarried couples are also starting families without first being married. Before 1960, this was very unusual, but in 2001, around 23% of births in the UK were to cohabiting couples.

Roles such as best man, godfather are only of _________ values

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 45 to 54

In comparison with most other places in the world, family identity is rather weak in Britain, especially in England. Of course, the family unit is still the basic living arrangement for most people. But in Britain this definitely means the nuclear family. There is little sense of extended family identity, except among some racial minorities. This is reflected in the size and composition of households.

It is unusual for adults of different generations within the family to live together. The average number of people living in each household in Britain is lower than in most other European countries. The proportion of elderly people living alone is similarly high.

Significant family events such as weddings, births and funerals are not automatically accompanied by large gatherings of people. It is still common to appoint people to certain roles on such
occasions, such as „best man‟ at a wedding, or godmother and godfather when a child is born. But for most people these appointments are of sentimental significance only. They do not imply lifelong responsibility. In fact, family gatherings of any kind beyond the household unit are rare. For most people, they are confined to the Christmas period.

Even the stereotyped nuclear family of father, mother and children is becoming less common. Britain has a higher rate of divorce than anywhere else in Europe except Denmark and the proportion of children born outside marriage has risen dramatically and is also one of the highest (about a third of all births). However, these trends do not necessarily mean that the nuclear family is disappearing. Divorces have increased, but the majority of marriages in Britain (about 55%) do not break down. In addition, it is notable that about three-quarters of all births outside marriage are officially registered by both parents and more than half of the children concerned are born to parents who are living together at the time.

Today, in Britain, many couples, mostly in their twenties or thirties, live together without getting married. Only about 60% of those couples will eventually get married. 40% of children in Britain are born to these cohabiting parents. In 2000, around a quarter of unmarried people between the ages of 16 and 59 were cohabiting in Great Britain. Unmarried couples are also starting families without first being married. Before 1960, this was very unusual, but in 2001, around 23% of births in the UK were to cohabiting couples.

The most popular period for family gatherings yearly is ___________

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 45 to 54

In comparison with most other places in the world, family identity is rather weak in Britain, especially in England. Of course, the family unit is still the basic living arrangement for most people. But in Britain this definitely means the nuclear family. There is little sense of extended family identity, except among some racial minorities. This is reflected in the size and composition of households.

It is unusual for adults of different generations within the family to live together. The average number of people living in each household in Britain is lower than in most other European countries. The proportion of elderly people living alone is similarly high.

Significant family events such as weddings, births and funerals are not automatically accompanied by large gatherings of people. It is still common to appoint people to certain roles on such
occasions, such as „best man‟ at a wedding, or godmother and godfather when a child is born. But for most people these appointments are of sentimental significance only. They do not imply lifelong responsibility. In fact, family gatherings of any kind beyond the household unit are rare. For most people, they are confined to the Christmas period.

Even the stereotyped nuclear family of father, mother and children is becoming less common. Britain has a higher rate of divorce than anywhere else in Europe except Denmark and the proportion of children born outside marriage has risen dramatically and is also one of the highest (about a third of all births). However, these trends do not necessarily mean that the nuclear family is disappearing. Divorces have increased, but the majority of marriages in Britain (about 55%) do not break down. In addition, it is notable that about three-quarters of all births outside marriage are officially registered by both parents and more than half of the children concerned are born to parents who are living together at the time.

Today, in Britain, many couples, mostly in their twenties or thirties, live together without getting married. Only about 60% of those couples will eventually get married. 40% of children in Britain are born to these cohabiting parents. In 2000, around a quarter of unmarried people between the ages of 16 and 59 were cohabiting in Great Britain. Unmarried couples are also starting families without first being married. Before 1960, this was very unusual, but in 2001, around 23% of births in the UK were to cohabiting couples.

The divorce rate in Britain is the ______ in Europe.

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 45 to 54

In comparison with most other places in the world, family identity is rather weak in Britain, especially in England. Of course, the family unit is still the basic living arrangement for most people. But in Britain this definitely means the nuclear family. There is little sense of extended family identity, except among some racial minorities. This is reflected in the size and composition of households.

It is unusual for adults of different generations within the family to live together. The average number of people living in each household in Britain is lower than in most other European countries. The proportion of elderly people living alone is similarly high.

Significant family events such as weddings, births and funerals are not automatically accompanied by large gatherings of people. It is still common to appoint people to certain roles on such
occasions, such as „best man‟ at a wedding, or godmother and godfather when a child is born. But for most people these appointments are of sentimental significance only. They do not imply lifelong responsibility. In fact, family gatherings of any kind beyond the household unit are rare. For most people, they are confined to the Christmas period.

Even the stereotyped nuclear family of father, mother and children is becoming less common. Britain has a higher rate of divorce than anywhere else in Europe except Denmark and the proportion of children born outside marriage has risen dramatically and is also one of the highest (about a third of all births). However, these trends do not necessarily mean that the nuclear family is disappearing. Divorces have increased, but the majority of marriages in Britain (about 55%) do not break down. In addition, it is notable that about three-quarters of all births outside marriage are officially registered by both parents and more than half of the children concerned are born to parents who are living together at the time.

Today, in Britain, many couples, mostly in their twenties or thirties, live together without getting married. Only about 60% of those couples will eventually get married. 40% of children in Britain are born to these cohabiting parents. In 2000, around a quarter of unmarried people between the ages of 16 and 59 were cohabiting in Great Britain. Unmarried couples are also starting families without first being married. Before 1960, this was very unusual, but in 2001, around 23% of births in the UK were to cohabiting couples.

About 75% of the births outside marriage are _________

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 45 to 54

In comparison with most other places in the world, family identity is rather weak in Britain, especially in England. Of course, the family unit is still the basic living arrangement for most people. But in Britain this definitely means the nuclear family. There is little sense of extended family identity, except among some racial minorities. This is reflected in the size and composition of households.

It is unusual for adults of different generations within the family to live together. The average number of people living in each household in Britain is lower than in most other European countries. The proportion of elderly people living alone is similarly high.

Significant family events such as weddings, births and funerals are not automatically accompanied by large gatherings of people. It is still common to appoint people to certain roles on such
occasions, such as „best man‟ at a wedding, or godmother and godfather when a child is born. But for most people these appointments are of sentimental significance only. They do not imply lifelong responsibility. In fact, family gatherings of any kind beyond the household unit are rare. For most people, they are confined to the Christmas period.

Even the stereotyped nuclear family of father, mother and children is becoming less common. Britain has a higher rate of divorce than anywhere else in Europe except Denmark and the proportion of children born outside marriage has risen dramatically and is also one of the highest (about a third of all births). However, these trends do not necessarily mean that the nuclear family is disappearing. Divorces have increased, but the majority of marriages in Britain (about 55%) do not break down. In addition, it is notable that about three-quarters of all births outside marriage are officially registered by both parents and more than half of the children concerned are born to parents who are living together at the time.

Today, in Britain, many couples, mostly in their twenties or thirties, live together without getting married. Only about 60% of those couples will eventually get married. 40% of children in Britain are born to these cohabiting parents. In 2000, around a quarter of unmarried people between the ages of 16 and 59 were cohabiting in Great Britain. Unmarried couples are also starting families without first being married. Before 1960, this was very unusual, but in 2001, around 23% of births in the UK were to cohabiting couples.

The leading factor contributing to the increase in the number of single-parent family is __

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 45 to 54

In comparison with most other places in the world, family identity is rather weak in Britain, especially in England. Of course, the family unit is still the basic living arrangement for most people. But in Britain this definitely means the nuclear family. There is little sense of extended family identity, except among some racial minorities. This is reflected in the size and composition of households.

It is unusual for adults of different generations within the family to live together. The average number of people living in each household in Britain is lower than in most other European countries. The proportion of elderly people living alone is similarly high.

Significant family events such as weddings, births and funerals are not automatically accompanied by large gatherings of people. It is still common to appoint people to certain roles on such
occasions, such as „best man‟ at a wedding, or godmother and godfather when a child is born. But for most people these appointments are of sentimental significance only. They do not imply lifelong responsibility. In fact, family gatherings of any kind beyond the household unit are rare. For most people, they are confined to the Christmas period.

Even the stereotyped nuclear family of father, mother and children is becoming less common. Britain has a higher rate of divorce than anywhere else in Europe except Denmark and the proportion of children born outside marriage has risen dramatically and is also one of the highest (about a third of all births). However, these trends do not necessarily mean that the nuclear family is disappearing. Divorces have increased, but the majority of marriages in Britain (about 55%) do not break down. In addition, it is notable that about three-quarters of all births outside marriage are officially registered by both parents and more than half of the children concerned are born to parents who are living together at the time.

Today, in Britain, many couples, mostly in their twenties or thirties, live together without getting married. Only about 60% of those couples will eventually get married. 40% of children in Britain are born to these cohabiting parents. In 2000, around a quarter of unmarried people between the ages of 16 and 59 were cohabiting in Great Britain. Unmarried couples are also starting families without first being married. Before 1960, this was very unusual, but in 2001, around 23% of births in the UK were to cohabiting couples.

The word reflected in paragraph 1 is closest in meaning to _______

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 45 to 54

In comparison with most other places in the world, family identity is rather weak in Britain, especially in England. Of course, the family unit is still the basic living arrangement for most people. But in Britain this definitely means the nuclear family. There is little sense of extended family identity, except among some racial minorities. This is reflected in the size and composition of households.

It is unusual for adults of different generations within the family to live together. The average number of people living in each household in Britain is lower than in most other European countries. The proportion of elderly people living alone is similarly high.

Significant family events such as weddings, births and funerals are not automatically accompanied by large gatherings of people. It is still common to appoint people to certain roles on such
occasions, such as „best man‟ at a wedding, or godmother and godfather when a child is born. But for most people these appointments are of sentimental significance only. They do not imply lifelong responsibility. In fact, family gatherings of any kind beyond the household unit are rare. For most people, they are confined to the Christmas period.

Even the stereotyped nuclear family of father, mother and children is becoming less common. Britain has a higher rate of divorce than anywhere else in Europe except Denmark and the proportion of children born outside marriage has risen dramatically and is also one of the highest (about a third of all births). However, these trends do not necessarily mean that the nuclear family is disappearing. Divorces have increased, but the majority of marriages in Britain (about 55%) do not break down. In addition, it is notable that about three-quarters of all births outside marriage are officially registered by both parents and more than half of the children concerned are born to parents who are living together at the time.

Today, in Britain, many couples, mostly in their twenties or thirties, live together without getting married. Only about 60% of those couples will eventually get married. 40% of children in Britain are born to these cohabiting parents. In 2000, around a quarter of unmarried people between the ages of 16 and 59 were cohabiting in Great Britain. Unmarried couples are also starting families without first being married. Before 1960, this was very unusual, but in 2001, around 23% of births in the UK were to cohabiting couples.

The word cohabiting in paragraph 5 is closest in meaning to __________

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 45 to 54

In comparison with most other places in the world, family identity is rather weak in Britain, especially in England. Of course, the family unit is still the basic living arrangement for most people. But in Britain this definitely means the nuclear family. There is little sense of extended family identity, except among some racial minorities. This is reflected in the size and composition of households.

It is unusual for adults of different generations within the family to live together. The average number of people living in each household in Britain is lower than in most other European countries. The proportion of elderly people living alone is similarly high.

Significant family events such as weddings, births and funerals are not automatically accompanied by large gatherings of people. It is still common to appoint people to certain roles on such
occasions, such as „best man‟ at a wedding, or godmother and godfather when a child is born. But for most people these appointments are of sentimental significance only. They do not imply lifelong responsibility. In fact, family gatherings of any kind beyond the household unit are rare. For most people, they are confined to the Christmas period.

Even the stereotyped nuclear family of father, mother and children is becoming less common. Britain has a higher rate of divorce than anywhere else in Europe except Denmark and the proportion of children born outside marriage has risen dramatically and is also one of the highest (about a third of all births). However, these trends do not necessarily mean that the nuclear family is disappearing. Divorces have increased, but the majority of marriages in Britain (about 55%) do not break down. In addition, it is notable that about three-quarters of all births outside marriage are officially registered by both parents and more than half of the children concerned are born to parents who are living together at the time.

Today, in Britain, many couples, mostly in their twenties or thirties, live together without getting married. Only about 60% of those couples will eventually get married. 40% of children in Britain are born to these cohabiting parents. In 2000, around a quarter of unmarried people between the ages of 16 and 59 were cohabiting in Great Britain. Unmarried couples are also starting families without first being married. Before 1960, this was very unusual, but in 2001, around 23% of births in the UK were to cohabiting couples.

What is the most suitable heading for paragraph 4?

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 45 to 54

In comparison with most other places in the world, family identity is rather weak in Britain, especially in England. Of course, the family unit is still the basic living arrangement for most people. But in Britain this definitely means the nuclear family. There is little sense of extended family identity, except among some racial minorities. This is reflected in the size and composition of households.

It is unusual for adults of different generations within the family to live together. The average number of people living in each household in Britain is lower than in most other European countries. The proportion of elderly people living alone is similarly high.

Significant family events such as weddings, births and funerals are not automatically accompanied by large gatherings of people. It is still common to appoint people to certain roles on such
occasions, such as „best man‟ at a wedding, or godmother and godfather when a child is born. But for most people these appointments are of sentimental significance only. They do not imply lifelong responsibility. In fact, family gatherings of any kind beyond the household unit are rare. For most people, they are confined to the Christmas period.

Even the stereotyped nuclear family of father, mother and children is becoming less common. Britain has a higher rate of divorce than anywhere else in Europe except Denmark and the proportion of children born outside marriage has risen dramatically and is also one of the highest (about a third of all births). However, these trends do not necessarily mean that the nuclear family is disappearing. Divorces have increased, but the majority of marriages in Britain (about 55%) do not break down. In addition, it is notable that about three-quarters of all births outside marriage are officially registered by both parents and more than half of the children concerned are born to parents who are living together at the time.

Today, in Britain, many couples, mostly in their twenties or thirties, live together without getting married. Only about 60% of those couples will eventually get married. 40% of children in Britain are born to these cohabiting parents. In 2000, around a quarter of unmarried people between the ages of 16 and 59 were cohabiting in Great Britain. Unmarried couples are also starting families without first being married. Before 1960, this was very unusual, but in 2001, around 23% of births in the UK were to cohabiting couples.

What is the most suitable title for the whole passage?

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm

What does the passage mainly discuss?

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm

The word "adversely" in the first paragraph is closest in meaning to _______.

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm

It can be inferred from the first paragraph that _______.

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm

The word "These" in the second paragraph is closest in meaning to________.

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm

For which of the following reasons can natural pollutants play an important role in controlling air pollution?

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm

According to the passage, human-generated air pollution in localized regions _______

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm

The word "localized" in the third paragraph is closest in meaning to _______.

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm

According to the passage, the numerical value of the concentration level of a substance is only useful if _______.

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm

The word "detectable" in the third paragraph is closest in meaning to_________

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm

Which of the following is best supported by the passage?