IV: which of the underlined part of these sentences is correct 2,There was somebody in the house because they was LIGHT/A LIGHT on inside 3,What would it be like to travel at the speed of LIGHT/A LI...

MD

Minh Di

31 tháng 5 2018

IV: which of the underlined part of these sentences is correct

2,There was somebody in the house because they was LIGHT/A LIGHT on inside

3,What would it be like to travel at the speed of LIGHT/A LIGHT?

4,I didn't have TIME/A TIME for breakfast

5,We has WONDERFUL TIME/A WONDERFUL TIME in Paris

#Tiếng anh lớp 7

2

KH

Kiêm Hùng

31 tháng 5 2018

IV: which of the underlined part of these sentences is correct

2,There was somebody in the house because they was LIGHT/A LIGHT on inside

3,What would it be like to travel at the speed of LIGHT/A LIGHT?

4,I didn't have TIME/A TIME for breakfast

5,We has WONDERFUL TIME/A WONDERFUL TIME in Paris

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CQ

cố quên một người

31 tháng 5 2018

1. A LIGHT

2. LIGHT

3. TIME

4. A WONDERFUL TIME

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BN

Bỉ Ngạn Xanh

16 tháng 2 2020

1. Read the passage and answer the questions. The first traffic control device appeared near the British House of Parliament at the intersection of George and Bridge Streets. The device was made in response to the desire by a Select Committee to use railway signals on highways. The device had lights and it used arms which extended outwards. It was operated manually by a police officer. The signal was 22 feet high and crowned with a gas light. The light was called semaphore and had arms that...

Đọc tiếp

1. Read the passage and answer the questions.

The first traffic control device appeared near the British House of Parliament at the intersection of George and Bridge Streets. The device was made in response to the desire by a Select Committee to use railway signals on highways. The device had lights and it used arms which extended outwards. It was operated manually by a police officer. The signal was 22 feet high and crowned with a gas light. The light was called semaphore and had arms that would extend horizontally that commanded drivers to "Stop" and then the arms would lower to a 45 degrees angle to tell drivers to proceed with "Caution". At night a red light would command "Stop" and a green light would mean use "Caution". The man behind this new and different invention was John Peake Knight a railroad engineer. The main reason for the traffic light was that there was an overflow of horse-drawn traffic over Westminster Bridge which forced thousands of pedestrians to walk next to the house of Parliament. But Knight's invention was not to last long. After only a month of use the device exploded and injured the police officer who was operating the light. In the first two decades of the 20th century semaphore traffic signals, like the one in London, were in use all over the United States with each state having its own design of the device. One good example was from Toledo, Ohio in 1908. The words "Stop" and "Go" were in white on a green background and the lights had red and green lenses illuminated by kerosene lamps for night travelers and the arms where eight feet above ground. Controlled by a traffic officer who would blow a whistle before changing the commands on this signal to help alert travelers of the change, the design was also used in Philadelphia and Detroit. The example in Ohio was the first time America tried to use a more visible form of traffic control that evolved the use of semaphore. The device that was used in Ohio was designed based on the use of railroad signals.

1. What was the main purpose of making the first traffic control device?

_____________________________

2. What was the light operated manually by a police officer called?

_____________________________

3. Why wasn't John Peake Knight's invention to last long?

_____________________________

4. How tall were the arms of the traffic lights used in Ohio in 1908?

____________________________

5. The Westminster Bridge is in .

A. America B. England C. Brazil D. Canada

#Tiếng anh lớp 7

1

NV

Nguoi Viet Nam

16 tháng 2 2020

1.The device was made in response to the desire by a Select Committee to use railway signals on highways.

2.The light was called semaphore.

3.But Knight's invention was not to last long. After only a month of use the device exploded and injured the police officer who was operating the light.

4.Toledo, Ohio in 1908, the arms where eight feet above ground.

5.B

Chúc bạn học tốt!

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LQ

Lê Quỳnh Anh

22 tháng 2 2019

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42. Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed....

Đọc tiếp

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, ﬁreﬂies the most common, an additional compound called ATP is required.

The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous ﬂuid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrogen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, speciﬁc to the plants and animals that produce them.

Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and ﬁnally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

Question 36: Which of the following is the main topic of the passage?

A. Cold light

B. Luciferase

C. Primitive plants and animals

D. Earth’s atmosphere

#Mẫu giáo

1

DH

Dương Hoàn Anh

22 tháng 2 2019

Đáp án A

Dịch nghĩa: Chủ đề chính của bài viết là gì?

A. Ánh sáng lạnh

B. Luciferase

C. Thực vật và động vật nguyên thủy

D. Khi hậu trên trái đất

Giải thích: Ta thấy đoạn văn chủ yếu nói về bioluminescence (sự phát quang sinh học) hay còn gọi là cold light (ánh sáng lạnh)

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LQ

Lê Quỳnh Anh

21 tháng 11 2018

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 38 to 42. (1) Just as optical fibers have transformed communication, they are also revolutionizing medicine. These ultra- thin, flexible fibers have opened a window into the living tissues of the body. By inserting optical fibers through natural openings or small incisions and threading them along the body's established pathways, physicians can look into...

Đọc tiếp

#Mẫu giáo

1

DH

Dương Hoàn Anh

21 tháng 11 2018

Đáp án D

A. Sự phát triển trong ngành truyền thông

B. Sự phát minh ra cáp quang

C. Công nghệ phẫu thuật mới

D. Vai trò của sợi quang trong y học
Câu đầu tiên đã nói lên chủ đề của toàn bài: “Just as optical fibers have transformed communication, they are also revolutionizing medicine.” (Chúng cải tiến y học). Những câu tiếp theo giải thích rõ vai trò của chúng: “…have open a window into the living tissiues of the body”, “By inserting optical fibers…, physicians can look into the lungs, intestines, heart and other areas”, “used to deliver laser light”, “These techniques have reduced the risk and the cost of medical care.” …=> Đáp án D.

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DM

Dương Minh

3 tháng 9 2019

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. Lighthouses are towers with strong lights that help mariners plot their position, inform them that land is near, and warn them of dangerous rocks and reefs. They are placed at prominent points on the coast and on islands, reefs, and sandbars. Every lighthouse has a distinctive pattern of light known as its characteristic. There are five basic...

Đọc tiếp

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.

Lighthouses are towers with strong lights that help mariners plot their position, inform them that land is near, and warn them of dangerous rocks and reefs. They are placed at prominent points on the coast and on islands, reefs, and sandbars.

Every lighthouse has a distinctive pattern of light known as its characteristic. There are five basic characteristics: fixed, flashing, occulting, group flashing, and group occulting. A fixed signal is a steady beam. A flashing signal has periods of darkness longer than periods of light, while an occulting signal’s periods of light are longer. A group-flashing light gives off two or more flashes at regular intervals, and a group - occulting signal consists of a fixed light with two or more periods of darkness at regular intervals. Some lighthouses use lights of different colors as well, and today, most lighthouses are also equipped with radio beacons. The three types of apparatus used to produce the signals are the catoptric, in which metal is used to reflect the light; the dioptric, in which glass is used; and the catadioptric, in which both glass and metal are used.

In the daytime, lighthouses can usually be identified by their structure alone. The most typical structure is a tower tapering at the top, but some, such as the Bastion Lighthouse on the Saint Lawrence River, are shaped like pyramids, and others, such as the Race Rock light, look like wooden houses sitting on high platforms. Still others, such as The American Shoal lighthouse off the Florida Coast, are skeletal towers of steel. Where lighthouses might be contused in daylight, they can be distinguished by day- marker patterns - designed of checks and stripes painted in vivid colors on lighthouse walls.

In the past, the job of lighthouse keeper was lonely and difficult if somewhat romantic. Lighthouse keepers put in hours of tedious work maintaining the lights. Today, lighthouses are almost entirely automated with humans supplying only occasional maintenance. Because of improvements in navigational technology, the importance of lighthouses has diminished. There are only about 340 functioning lighthouses in existence in the United States today, compared to about 1,500 in 1900, and there are only about 1,400 functioning lighthouses outside the United States. Some decommissioned lighthouses have been preserved as historical monument.

According to the passage, what kind of signal has long periods of light that are regularly broken by two or more periods of darkness?

A. Flashing

B. Group occulting

C. occulting

D. Group flashing

#Mẫu giáo

1

NH

Nguyen Hoang Hai

3 tháng 9 2019

Đáp án B.

Key words: kind of signal, long periods of light broken by two or more periods of darkness

Clue: a group-occulting signal consist of a fixed light with two or more periods of darkness at regular intervals: tín hiệu ánh sáng lấp ló theo nhóm bao gồm một ánh sáng cố định với hai hoặc nhiều chu kỳ tối diễn ra trong những khoảng cách đều đặn

Vậy đáp án chính xác là B. Group occulting

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LQ

Lê Quỳnh Anh

23 tháng 8 2017

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. Lighthouses are towers with strong lights that help mariners plot their position, inform them that land is near, and warn them of dangerous rocks and reefs. They are placed at prominent points on the coast and on islands, reefs, and sandbars. Every lighthouse has a distinctive pattern of light known as its characteristic. There are five basic...

Đọc tiếp

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.

Lighthouses are towers with strong lights that help mariners plot their position, inform them that land is near, and warn them of dangerous rocks and reefs. They are placed at prominent points on the coast and on islands, reefs, and sandbars.

Every lighthouse has a distinctive pattern of light known as its characteristic. There are five basic characteristics: fixed, flashing, occulting, group flashing, and group occulting. A fixed signal is a steady beam. A flashing signal has periods of darkness longer than periods of light, while an occulting signal’s periods of light are longer. A group-flashing light gives off two or more flashes at regular intervals, and a group - occulting signal consists of a fixed light with two or more periods of darkness at regular intervals. Some lighthouses use lights of different colors as well, and today, most lighthouses are also equipped with radio beacons. The three types of apparatus used to produce the signals are the catoptric, in which metal is used to reflect the light; the dioptric, in which glass is used; and the catadioptric, in which both glass and metal are used.

In the daytime, lighthouses can usually be identified by their structure alone. The most typical structure is a tower tapering at the top, but some, such as the Bastion Lighthouse on the Saint Lawrence River, are shaped like pyramids, and others, such as the Race Rock light, look like wooden houses sitting on high platforms. Still others, such as The American Shoal lighthouse off the Florida Coast, are skeletal towers of steel. Where lighthouses might be contused in daylight, they can be distinguished by day- marker patterns - designed of checks and stripes painted in vivid colors on lighthouse walls.

In the past, the job of lighthouse keeper was lonely and difficult if somewhat romantic. Lighthouse keepers put in hours of tedious work maintaining the lights. Today, lighthouses are almost entirely automated with humans supplying only occasional maintenance. Because of improvements in navigational technology, the importance of lighthouses has diminished. There are only about 340 functioning lighthouses in existence in the United States today, compared to about 1,500 in 1900, and there are only about 1,400 functioning lighthouses outside the United States. Some decommissioned lighthouses have been preserved as historical monument.

According to the passage, what kind of signal has long periods of light that are regularly broken by two or more periods of darkness?

A. Flashing

B. Group occulting

C. occulting

D. Group flashing

#Mẫu giáo

1

DH

Dương Hoàn Anh

23 tháng 8 2017

Đáp án B.

Key words: kind of signal, long periods of light broken by two or more periods of darkness

Clue: a group-occulting signal consist of a fixed light with two or more periods of darkness at regular intervals: tín hiệu ánh sáng lấp ló theo nhóm bao gồm một ánh sáng cố định với hai hoặc nhiều chu kỳ tối diễn ra trong những khoảng cách đều đặn

Vậy đáp án chính xác là B. Group occulting

Đúng(0)

LQ

Lê Quỳnh Anh

21 tháng 2 2018

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42. Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed....

Đọc tiếp

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, ﬁreﬂies the most common, an additional compound called ATP is required.

The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous ﬂuid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrogen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, speciﬁc to the plants and animals that produce them.

Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and ﬁnally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

Question 40: Where in the passage does the author explain how living light occurs?

A. Line 3-4

B. Line 5-7

C. Line 8-l0

D. Line 10-12

#Mẫu giáo

1

DH

Dương Hoàn Anh

21 tháng 2 2018

Đáp án B

Dịch nghĩa: Ở đâu trong đoạn văn tác giả giải thích ánh sáng tự nhiên tồn tại như thế nào?

A. Dòng 3-4

B. Dòng 5-7

C. Dòng 8-10

D. Dòng 10-12

Giải thích: Thông tin nằm ở dòng 5-7 đoạn văn: “Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, ﬁreﬂies the most common, an additional compound called ATP is required” - “Ánh sáng sống diễn ra khi luciferin và oxy kết hợp với sự có mặt của luciferase. Trong một số ít trường hợp, phổ biến nhất đối với đom đóm, cần một chất hóa học khác là ATP.”

=> Có thể thấy trong 2 câu này tác giả đã giải thích quá trình hình thành của ánh sáng sống.

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LQ

Lê Quỳnh Anh

16 tháng 11 2018

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42. Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed....

Đọc tiếp

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, ﬁreﬂies the most common, an additional compound called ATP is required.

The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous ﬂuid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrogen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, speciﬁc to the plants and animals that produce them.

Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and ﬁnally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

Question 41: Bioluminescence is described as all of the following EXCEPT ______.

A. a complex chemicals process

B. an adaptation of early plants and animals to the environment

C. a form of cold light

D. a poisonous substance

#Mẫu giáo

1

DH

Dương Hoàn Anh

16 tháng 11 2018

Đáp án D

Dịch nghĩa: Sự phát quang sinh học được miêu tả như tất cả những điều sau NGOẠI TRỮ _______.

A. một quá trình hóa học phức tạp

B. một sự thích ứng của những loài động thực vật tiền sử với môi trường

C. một dạng ánh sáng lạnh

D. một chất có độc

Giải thích: Ta thấy các đáp án còn lại đều được nói đến như những đặc tính của sự phát quang sinh học:

A. Đoạn 1: “Although bioluminescence is a relatively complicated process, it can be reduced to simple terms” - “Mặc dù sự phát quang sinh học là một quá trình tương đối phức tạp, nó có thể được giảm xuống đến những khái niệm đơn giản.”

B. Đoạn cuối: “It is speculated that millions of years ago, all life may have produced light to survive” - “Người ta đoán rằng hàng triệu năm về trước, toàn bộ sự sống có thể đã phải tạo ra ánh sáng để sinh tồn.”

C. Câu đầu bài viết: “Light from a living plant or animal is called bioluminescence, or cold light...” - “Ánh sáng từ một loài động vật hay thực vật còn sống được gọi là sự phát quang sinh học, hay ánh sáng lạnh. . .”

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LQ

Lê Quỳnh Anh

24 tháng 3 2017

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42. Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed....

Đọc tiếp

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, ﬁreﬂies the most common, an additional compound called ATP is required.

The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous ﬂuid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrogen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, speciﬁc to the plants and animals that produce them.

Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and ﬁnally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

Question38: The word “primitive” is closest meaning to ______.

A. very old

B. very large

C. very important

D. very common

#Mẫu giáo

1

DH

Dương Hoàn Anh

24 tháng 3 2017

Đáp án A

Dịch nghĩa: Từ “primitive” gần nghĩa nhất với _______.

A. rất nhiều tuổi

B. rất lớn

C. rất quan trọng

D. rất phổ biến

Giải thích: be primitive: rất lâu đời, nguyên thủy = very old

Đúng(0)

LQ

Lê Quỳnh Anh

21 tháng 9 2019

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42. Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed....

Đọc tiếp

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, ﬁreﬂies the most common, an additional compound called ATP is required.

The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous ﬂuid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrogen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, speciﬁc to the plants and animals that produce them.

Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and ﬁnally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

Question 39: The word “it” refers to:

A. a plant

B. an animal

C. bioluminescence

D. incandescence

#Mẫu giáo

1

DH

Dương Hoàn Anh

21 tháng 9 2019

Đáp án C

Dịch nghĩa: Từ “it” để cập đến

A. một loài cây

B. một loài động vật

C. sự phát quang sinh học

D. sự cháy

Giải thích: Đọc câu đầu bài viết: “Light from a living plant or animal is called biolumines - cence, or cold light, to distinguish it from incandescence. . .” - “Ánh sáng từ một loài động hay thực vật còn sống được gọi là sự phát quang sinh học, hay ánh sáng lạnh, để phân biệt nó với sự cháy...”

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