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Câu hỏi:

27/08/2021 89

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_________.

A. cause deafness 

B. create hazardous working conditions 

Đáp án chính xác

C. influence ocean waves 

D. damage loudspeakers and sound equipment

Trả lời:

verified Giải bởi qa.haylamdo.com

Đáp án B

Thông tin ở câu cuối: … which causes fatigue that can impair the efficiency and alertness of the crew, and may mask the warning sounds of alarm and fog signals.

(những âm thanh không mong muốn có thể gây mệt mỏi, ảnh hưởng đến năng suất và sự tỉnh táo của phi hành đoàn, và có thể che mất âm thanh cảnh báo và tín hiệu bão => tạo ra tình trạng làm việc nguy hiểm)

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CÂU HỎI HOT CÙNG CHỦ ĐỀ

Câu 1:

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.

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Câu 2:

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________.

Xem đáp án » 27/08/2021 888

Câu 3:

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________.

Xem đáp án » 27/08/2021 775

Câu 4:

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________.

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Câu 5:

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.

Xem đáp án » 27/08/2021 681

Câu 6:

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.

Xem đáp án » 27/08/2021 556

Câu 7:

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.

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Câu 8:

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.

Xem đáp án » 27/08/2021 458

Câu 9:

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.

Xem đáp án » 27/08/2021 417

Câu 10:

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.

Xem đáp án » 27/08/2021 392

Câu 11:

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________.

Xem đáp án » 27/08/2021 372

Câu 12:

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.

Xem đáp án » 27/08/2021 360

Câu 13:

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.

Xem đáp án » 27/08/2021 349

Câu 14:

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________.

Xem đáp án » 27/08/2021 344

Câu 15:

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.

Xem đáp án » 27/08/2021 332

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