Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs 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 differs 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 has underlined part pronounced differently from the rests.

Mark the letter A, B, C, or D on your answer sheet to indicate the word that has underlined part pronounced differently from the rests.

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

I’ll take the new job whose salary is fantastic.

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

Ralph Nader was the most prominent leader of the U.S consumer protection movement.

Mark the letter A, B, C, or D on your answer sheet to indicate the word (s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.

A chronic lack of sleep may make us irritable and reduces our motivation to work.

Mark the letter A, B, C, or D on your answer sheet to indicate the word (s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.

Fruit and vegetables grew in abundance on the island. The islanders even exported the surplus.

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.

When you wave to a friend, you are using sign language. When you smile at someone, you mean to be (9) ______. When you put one finger in front of your (10) ______, you mean, "Be quiet." Yet, people in different countries may use different sign languages. Once an Englishman was in Italy he could speak a little Italian. One day while he was walking in the street, he felt (11) ______ and went into a restaurant. When the waiter came, the Englishman opened his mouth, put his fingers into it and took them out again and moved his lips. In this way, he meant to say, "Bring me something to eat." But the waiter brought him a lot of things to (12) ______: first tea, then coffee, then milk, but no food. The Englishman was sorry that he was not able to tell the waiter he was hungry. He was eardy to leave the restaurant. When another man came in and put his hands on his stomach. And this sign was (13) ______ enough for the waiter. In a few minutes, the waiter brought him a large plate of bread and meat. At last, the Englishman had his meal in the same way.

Điền ô số 9

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.

When you wave to a friend, you are using sign language. When you smile at someone, you mean to be (9) ______. When you put one finger in front of your (10) ______, you mean, "Be quiet." Yet, people in different countries may use different sign languages. Once an Englishman was in Italy he could speak a little Italian. One day while he was walking in the street, he felt (11) ______ and went into a restaurant. When the waiter came, the Englishman opened his mouth, put his fingers into it and took them out again and moved his lips. In this way, he meant to say, "Bring me something to eat." But the waiter brought him a lot of things to (12) ______: first tea, then coffee, then milk, but no food. The Englishman was sorry that he was not able to tell the waiter he was hungry. He was eardy to leave the restaurant. When another man came in and put his hands on his stomach. And this sign was (13) ______ enough for the waiter. In a few minutes, the waiter brought him a large plate of bread and meat. At last, the Englishman had his meal in the same way.

Điền ô số 10

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.

When you wave to a friend, you are using sign language. When you smile at someone, you mean to be (9) ______. When you put one finger in front of your (10) ______, you mean, "Be quiet." Yet, people in different countries may use different sign languages. Once an Englishman was in Italy he could speak a little Italian. One day while he was walking in the street, he felt (11) ______ and went into a restaurant. When the waiter came, the Englishman opened his mouth, put his fingers into it and took them out again and moved his lips. In this way, he meant to say, "Bring me something to eat." But the waiter brought him a lot of things to (12) ______: first tea, then coffee, then milk, but no food. The Englishman was sorry that he was not able to tell the waiter he was hungry. He was eardy to leave the restaurant. When another man came in and put his hands on his stomach. And this sign was (13) ______ enough for the waiter. In a few minutes, the waiter brought him a large plate of bread and meat. At last, the Englishman had his meal in the same way.

Điền ô số 11

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.

When you wave to a friend, you are using sign language. When you smile at someone, you mean to be (9) ______. When you put one finger in front of your (10) ______, you mean, "Be quiet." Yet, people in different countries may use different sign languages. Once an Englishman was in Italy he could speak a little Italian. One day while he was walking in the street, he felt (11) ______ and went into a restaurant. When the waiter came, the Englishman opened his mouth, put his fingers into it and took them out again and moved his lips. In this way, he meant to say, "Bring me something to eat." But the waiter brought him a lot of things to (12) ______: first tea, then coffee, then milk, but no food. The Englishman was sorry that he was not able to tell the waiter he was hungry. He was eardy to leave the restaurant. When another man came in and put his hands on his stomach. And this sign was (13) ______ enough for the waiter. In a few minutes, the waiter brought him a large plate of bread and meat. At last, the Englishman had his meal in the same way.

Điền ô số 12

Mark the letter A, B , C, or D on your answer sheet to indicate the most suitable response to the following situations.

- Ivan: I have stacks of homework to do. 

- Kyle: _________________ !

Mark the letter A, B , C, or D on your answer sheet to indicate the most suitable response to the following situations.

- Tom: I'm going on holiday tomorrow.

- Jerry: _________ !

Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction.

Both bowling and ice-skating was introduced by the Dutch who colonized the New World in the 1600's.

Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction.

There are a large supply of pens and notebooks in the storeroom to the left of the library entrance.

Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction.

There are many ways to preserve fruit, for example freezing, canning and to dry.

Mark the letter A, B, C, or D on your answer sheet to show the option that best makes the meaningful sentence.

person’s choice / occupations / probably / most important / have / made.

Mark the letter A, B, C, or D on your answer sheet to show the option that best makes the meaningful sentence.

my opinion / unfair / women / more duties / husbands.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Algae is a primitive form of life, a single-celled or simple multiple-celled organism that is able to conduct the process of photosynthesis. It is generally found in water but can also be found elsewhere, growing on such surfaces as rocks or trees. The various types of algae are classified according to pigment.

Blue-green algae, or Cyanophyta, can grow at very high temperatures and under high-intensity light. This type of algae is the oldest form of life with photosynthetic capabilities. Fossilized remains of blue-green algae more than 3.4 billion years old have been found in parts of Africa.

Green algae, or Chlorophyta, is generally found in fresh water. It reproduces on the surfaces of enclosed bodies of water such as ponds or lakes and has the appearance of a fuzzy green coating on the surface of the water.

Brown algae, or Phaeophyta, grows in shallow, temperate water. This type of algae is the largest in size and is most recognizable as a type of seaweed. Its long stalks can be enmeshed on the ocean floor, or it can float freely on the ocean's surface. 

Red algae, or Rhodophyta, is a small, delicate organism found in the deep waters of the subtropics. This type of algae has an essential role in the formation of coral reefs: it secretes lime from the seawater to foster the formation of limestone deposits.

What is the author's main purpose?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Algae is a primitive form of life, a single-celled or simple multiple-celled organism that is able to conduct the process of photosynthesis. It is generally found in water but can also be found elsewhere, growing on such surfaces as rocks or trees. The various types of algae are classified according to pigment.

Blue-green algae, or Cyanophyta, can grow at very high temperatures and under high-intensity light. This type of algae is the oldest form of life with photosynthetic capabilities. Fossilized remains of blue-green algae more than 3.4 billion years old have been found in parts of Africa.

Green algae, or Chlorophyta, is generally found in fresh water. It reproduces on the surfaces of enclosed bodies of water such as ponds or lakes and has the appearance of a fuzzy green coating on the surface of the water.

Brown algae, or Phaeophyta, grows in shallow, temperate water. This type of algae is the largest in size and is most recognizable as a type of seaweed. Its long stalks can be enmeshed on the ocean floor, or it can float freely on the ocean's surface. 

Red algae, or Rhodophyta, is a small, delicate organism found in the deep waters of the subtropics. This type of algae has an essential role in the formation of coral reefs: it secretes lime from the seawater to foster the formation of limestone deposits.

Which of the following is NOT true about algae?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Algae is a primitive form of life, a single-celled or simple multiple-celled organism that is able to conduct the process of photosynthesis. It is generally found in water but can also be found elsewhere, growing on such surfaces as rocks or trees. The various types of algae are classified according to pigment.

Blue-green algae, or Cyanophyta, can grow at very high temperatures and under high-intensity light. This type of algae is the oldest form of life with photosynthetic capabilities. Fossilized remains of blue-green algae more than 3.4 billion years old have been found in parts of Africa.

Green algae, or Chlorophyta, is generally found in fresh water. It reproduces on the surfaces of enclosed bodies of water such as ponds or lakes and has the appearance of a fuzzy green coating on the surface of the water.

Brown algae, or Phaeophyta, grows in shallow, temperate water. This type of algae is the largest in size and is most recognizable as a type of seaweed. Its long stalks can be enmeshed on the ocean floor, or it can float freely on the ocean's surface. 

Red algae, or Rhodophyta, is a small, delicate organism found in the deep waters of the subtropics. This type of algae has an essential role in the formation of coral reefs: it secretes lime from the seawater to foster the formation of limestone deposits.

The word "pigment" at the end of the first paragraph means________.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Algae is a primitive form of life, a single-celled or simple multiple-celled organism that is able to conduct the process of photosynthesis. It is generally found in water but can also be found elsewhere, growing on such surfaces as rocks or trees. The various types of algae are classified according to pigment.

Blue-green algae, or Cyanophyta, can grow at very high temperatures and under high-intensity light. This type of algae is the oldest form of life with photosynthetic capabilities. Fossilized remains of blue-green algae more than 3.4 billion years old have been found in parts of Africa.

Green algae, or Chlorophyta, is generally found in fresh water. It reproduces on the surfaces of enclosed bodies of water such as ponds or lakes and has the appearance of a fuzzy green coating on the surface of the water.

Brown algae, or Phaeophyta, grows in shallow, temperate water. This type of algae is the largest in size and is most recognizable as a type of seaweed. Its long stalks can be enmeshed on the ocean floor, or it can float freely on the ocean's surface. 

Red algae, or Rhodophyta, is a small, delicate organism found in the deep waters of the subtropics. This type of algae has an essential role in the formation of coral reefs: it secretes lime from the seawater to foster the formation of limestone deposits.

Algae remnants found in Africa are________.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Algae is a primitive form of life, a single-celled or simple multiple-celled organism that is able to conduct the process of photosynthesis. It is generally found in water but can also be found elsewhere, growing on such surfaces as rocks or trees. The various types of algae are classified according to pigment.

Blue-green algae, or Cyanophyta, can grow at very high temperatures and under high-intensity light. This type of algae is the oldest form of life with photosynthetic capabilities. Fossilized remains of blue-green algae more than 3.4 billion years old have been found in parts of Africa.

Green algae, or Chlorophyta, is generally found in fresh water. It reproduces on the surfaces of enclosed bodies of water such as ponds or lakes and has the appearance of a fuzzy green coating on the surface of the water.

Brown algae, or Phaeophyta, grows in shallow, temperate water. This type of algae is the largest in size and is most recognizable as a type of seaweed. Its long stalks can be enmeshed on the ocean floor, or it can float freely on the ocean's surface. 

Red algae, or Rhodophyta, is a small, delicate organism found in the deep waters of the subtropics. This type of algae has an essential role in the formation of coral reefs: it secretes lime from the seawater to foster the formation of limestone deposits.

Green algae is generally found________.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Algae is a primitive form of life, a single-celled or simple multiple-celled organism that is able to conduct the process of photosynthesis. It is generally found in water but can also be found elsewhere, growing on such surfaces as rocks or trees. The various types of algae are classified according to pigment.

Blue-green algae, or Cyanophyta, can grow at very high temperatures and under high-intensity light. This type of algae is the oldest form of life with photosynthetic capabilities. Fossilized remains of blue-green algae more than 3.4 billion years old have been found in parts of Africa.

Green algae, or Chlorophyta, is generally found in fresh water. It reproduces on the surfaces of enclosed bodies of water such as ponds or lakes and has the appearance of a fuzzy green coating on the surface of the water.

Brown algae, or Phaeophyta, grows in shallow, temperate water. This type of algae is the largest in size and is most recognizable as a type of seaweed. Its long stalks can be enmeshed on the ocean floor, or it can float freely on the ocean's surface. 

Red algae, or Rhodophyta, is a small, delicate organism found in the deep waters of the subtropics. This type of algae has an essential role in the formation of coral reefs: it secretes lime from the seawater to foster the formation of limestone deposits.

Brown algae would most likely be found________.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Algae is a primitive form of life, a single-celled or simple multiple-celled organism that is able to conduct the process of photosynthesis. It is generally found in water but can also be found elsewhere, growing on such surfaces as rocks or trees. The various types of algae are classified according to pigment.

Blue-green algae, or Cyanophyta, can grow at very high temperatures and under high-intensity light. This type of algae is the oldest form of life with photosynthetic capabilities. Fossilized remains of blue-green algae more than 3.4 billion years old have been found in parts of Africa.

Green algae, or Chlorophyta, is generally found in fresh water. It reproduces on the surfaces of enclosed bodies of water such as ponds or lakes and has the appearance of a fuzzy green coating on the surface of the water.

Brown algae, or Phaeophyta, grows in shallow, temperate water. This type of algae is the largest in size and is most recognizable as a type of seaweed. Its long stalks can be enmeshed on the ocean floor, or it can float freely on the ocean's surface. 

Red algae, or Rhodophyta, is a small, delicate organism found in the deep waters of the subtropics. This type of algae has an essential role in the formation of coral reefs: it secretes lime from the seawater to foster the formation of limestone deposits.

According to the passage, red algae is________.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Algae is a primitive form of life, a single-celled or simple multiple-celled organism that is able to conduct the process of photosynthesis. It is generally found in water but can also be found elsewhere, growing on such surfaces as rocks or trees. The various types of algae are classified according to pigment.

Blue-green algae, or Cyanophyta, can grow at very high temperatures and under high-intensity light. This type of algae is the oldest form of life with photosynthetic capabilities. Fossilized remains of blue-green algae more than 3.4 billion years old have been found in parts of Africa.

Green algae, or Chlorophyta, is generally found in fresh water. It reproduces on the surfaces of enclosed bodies of water such as ponds or lakes and has the appearance of a fuzzy green coating on the surface of the water.

Brown algae, or Phaeophyta, grows in shallow, temperate water. This type of algae is the largest in size and is most recognizable as a type of seaweed. Its long stalks can be enmeshed on the ocean floor, or it can float freely on the ocean's surface. 

Red algae, or Rhodophyta, is a small, delicate organism found in the deep waters of the subtropics. This type of algae has an essential role in the formation of coral reefs: it secretes lime from the seawater to foster the formation of limestone deposits.

It can be inferred from the passage that limestone deposits serve as the basis of________.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following sentences.

Their chances of success are small.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following sentences.

“Would you like something to drink?” he asked.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following sentences.

Public education is so good in European countries that there is almost no demand for private schools

Mark the letter A, B , C, or D on your answer sheet to indicate the correct answer to each of the following questions.

The woman________ last week has been freed by the police.

Mark the letter A, B , C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Why don't you raise your hand to________ the teacher's attention in stead of shouting like this?

Mark the letter A, B , C, or D on your answer sheet to indicate the correct answer to each of the following questions.

She has just enrolled on a ________ course in cooking because she is getting married next month.

Mark the letter A, B , C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Many workers switch from the day________ to the night one with difficulties.

Mark the letter A, B , C, or D on your answer sheet to indicate the correct answer to each of the following questions.

The Internet enables users of computers to ________ information in a variety of forms.

Mark the letter A, B , C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Women in American have a lot of ________ freedom.

Mark the letter A, B , C, or D on your answer sheet to indicate the correct answer to each of the following questions.

The survey was to find out the young people’s attitudes________ love and marriage.

Mark the letter A, B , C, or D on your answer sheet to indicate the correct answer to each of the following questions.

John ________ the keys. I cannot see it anywhere.

Mark the letter A, B , C, or D on your answer sheet to indicate the correct answer to each of the following questions.

I would really like to join you on a skiing trip but I can't do it until I________ my thesis.

Mark the letter A, B , C, or D on your answer sheet to indicate the correct answer to each of the following questions.

________ he studied hard, he didn't pass his final exams.

Mark the letter A, B , C, or D on your answer sheet to indicate the correct answer to each of the following questions.

To be honest, Harry has________ than you have.

Mark the letter A, B , C, or D on your answer sheet to indicate the correct answer to each of the following questions.

My new glasses cost me ________ the pair that I bought last month.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Sound moves form its source to the ear by wavelike fluctuations in air pressure, something like the crests and troughs of ocean waves. Once way to keep from hearing sound is to use ear plugs. Another way is to cancel out the sound with anti-sound. Using a noisemarker controlled by a microprocessor, engineers have produced sound waves that are half a wavelength out of phase with those of the noise to be quieted-each crest is matched to a trough, and vice versa. Once the researchers have recorded the offending sound, a microprocessor calculates the amplitude and wavelength of sound that will cancel out the crests and troughs of noise. It then produces an electric current that is amplified and fed to a loudspeaker, which produces anti-sound and wipes out the noise. If the anti-sound goes out of synchronization, a microphone picks up the leftover sound and sends it back to the microprocessor, which changes the phase of the anti- sound just enough to cause complete silence.

The research team has concentrated on eliminating low-frequency noise from ship engines, which causes fatigue that can impair the efficiency and alertness of the crew, and may mask the warning sounds of alarm and fog signals.

What is the main purpose of the passage?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Sound moves form its source to the ear by wavelike fluctuations in air pressure, something like the crests and troughs of ocean waves. Once way to keep from hearing sound is to use ear plugs. Another way is to cancel out the sound with anti-sound. Using a noisemarker controlled by a microprocessor, engineers have produced sound waves that are half a wavelength out of phase with those of the noise to be quieted-each crest is matched to a trough, and vice versa. Once the researchers have recorded the offending sound, a microprocessor calculates the amplitude and wavelength of sound that will cancel out the crests and troughs of noise. It then produces an electric current that is amplified and fed to a loudspeaker, which produces anti-sound and wipes out the noise. If the anti-sound goes out of synchronization, a microphone picks up the leftover sound and sends it back to the microprocessor, which changes the phase of the anti- sound just enough to cause complete silence.

The research team has concentrated on eliminating low-frequency noise from ship engines, which causes fatigue that can impair the efficiency and alertness of the crew, and may mask the warning sounds of alarm and fog signals.

The passage compares sound to_________.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Sound moves form its source to the ear by wavelike fluctuations in air pressure, something like the crests and troughs of ocean waves. Once way to keep from hearing sound is to use ear plugs. Another way is to cancel out the sound with anti-sound. Using a noisemarker controlled by a microprocessor, engineers have produced sound waves that are half a wavelength out of phase with those of the noise to be quieted-each crest is matched to a trough, and vice versa. Once the researchers have recorded the offending sound, a microprocessor calculates the amplitude and wavelength of sound that will cancel out the crests and troughs of noise. It then produces an electric current that is amplified and fed to a loudspeaker, which produces anti-sound and wipes out the noise. If the anti-sound goes out of synchronization, a microphone picks up the leftover sound and sends it back to the microprocessor, which changes the phase of the anti- sound just enough to cause complete silence.

The research team has concentrated on eliminating low-frequency noise from ship engines, which causes fatigue that can impair the efficiency and alertness of the crew, and may mask the warning sounds of alarm and fog signals.

The passage discusses a way to deal with an offensive noise by_________.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Sound moves form its source to the ear by wavelike fluctuations in air pressure, something like the crests and troughs of ocean waves. Once way to keep from hearing sound is to use ear plugs. Another way is to cancel out the sound with anti-sound. Using a noisemarker controlled by a microprocessor, engineers have produced sound waves that are half a wavelength out of phase with those of the noise to be quieted-each crest is matched to a trough, and vice versa. Once the researchers have recorded the offending sound, a microprocessor calculates the amplitude and wavelength of sound that will cancel out the crests and troughs of noise. It then produces an electric current that is amplified and fed to a loudspeaker, which produces anti-sound and wipes out the noise. If the anti-sound goes out of synchronization, a microphone picks up the leftover sound and sends it back to the microprocessor, which changes the phase of the anti- sound just enough to cause complete silence.

The research team has concentrated on eliminating low-frequency noise from ship engines, which causes fatigue that can impair the efficiency and alertness of the crew, and may mask the warning sounds of alarm and fog signals.

The microprocessor described in the passage will probably be used for_________.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Sound moves form its source to the ear by wavelike fluctuations in air pressure, something like the crests and troughs of ocean waves. Once way to keep from hearing sound is to use ear plugs. Another way is to cancel out the sound with anti-sound. Using a noisemarker controlled by a microprocessor, engineers have produced sound waves that are half a wavelength out of phase with those of the noise to be quieted-each crest is matched to a trough, and vice versa. Once the researchers have recorded the offending sound, a microprocessor calculates the amplitude and wavelength of sound that will cancel out the crests and troughs of noise. It then produces an electric current that is amplified and fed to a loudspeaker, which produces anti-sound and wipes out the noise. If the anti-sound goes out of synchronization, a microphone picks up the leftover sound and sends it back to the microprocessor, which changes the phase of the anti- sound just enough to cause complete silence.

The research team has concentrated on eliminating low-frequency noise from ship engines, which causes fatigue that can impair the efficiency and alertness of the crew, and may mask the warning sounds of alarm and fog signals.

The researcher mentioned in the passage are concerned about unwanted noise because it can_________.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Sound moves form its source to the ear by wavelike fluctuations in air pressure, something like the crests and troughs of ocean waves. Once way to keep from hearing sound is to use ear plugs. Another way is to cancel out the sound with anti-sound. Using a noisemarker controlled by a microprocessor, engineers have produced sound waves that are half a wavelength out of phase with those of the noise to be quieted-each crest is matched to a trough, and vice versa. Once the researchers have recorded the offending sound, a microprocessor calculates the amplitude and wavelength of sound that will cancel out the crests and troughs of noise. It then produces an electric current that is amplified and fed to a loudspeaker, which produces anti-sound and wipes out the noise. If the anti-sound goes out of synchronization, a microphone picks up the leftover sound and sends it back to the microprocessor, which changes the phase of the anti- sound just enough to cause complete silence.

The research team has concentrated on eliminating low-frequency noise from ship engines, which causes fatigue that can impair the efficiency and alertness of the crew, and may mask the warning sounds of alarm and fog signals.

According to the passage, what group of people will probably first from the use of the microprocessor?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

Sound moves form its source to the ear by wavelike fluctuations in air pressure, something like the crests and troughs of ocean waves. Once way to keep from hearing sound is to use ear plugs. Another way is to cancel out the sound with anti-sound. Using a noisemarker controlled by a microprocessor, engineers have produced sound waves that are half a wavelength out of phase with those of the noise to be quieted-each crest is matched to a trough, and vice versa. Once the researchers have recorded the offending sound, a microprocessor calculates the amplitude and wavelength of sound that will cancel out the crests and troughs of noise. It then produces an electric current that is amplified and fed to a loudspeaker, which produces anti-sound and wipes out the noise. If the anti-sound goes out of synchronization, a microphone picks up the leftover sound and sends it back to the microprocessor, which changes the phase of the anti- sound just enough to cause complete silence.

The research team has concentrated on eliminating low-frequency noise from ship engines, which causes fatigue that can impair the efficiency and alertness of the crew, and may mask the warning sounds of alarm and fog signals.

A paragraph following the passage would most probably discuss_________.