ĐỀ THI THỬ THPT QUỐC GIA NĂM 2019 – LẦN 2 Môn thi: TIẾNG ANH (Đề 20)

Mark the letter A, B, C or D on your answer sheet to indicate the word that differs from the other three in the position of the primary 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 other three in the position of the primary stress in each of the following questions. 

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.

By adopting a few simple techniques, parents who read to their children can considerably increase their children’s language development. It is surprising, but true. How parents talk to their children makes a big difference in the children’s language development. If a parent encourages the child to actively respond to what the parent is reading, the child’s language skills increase.

A study was done with two or three-year-old children and their parents. Half of the thirty children participants were in the experimental study; the other half acted as the control group. In the experimental group, the parents were given a two-hour training session in which they were taught to ask open-ended questions rather than yes-no questions. For example, the parent should ask, “What is the doggy doing?” rather than, “Is the doggy running away?” Experimental parents were also instructed how to expand on their children’s answer, how to suggest alternative possibilities, and how to praise correct answers.

At the beginning of the study, the children did not differ on levels of language development, but at the end of one month, the children in the experimental group were 5.5 months ahead of the control group on a test of verbal expression and vocabulary. Nine months later, the children in the experimental group still showed an advance of 6 months over the children in the control group. 

Parents can give great help to their children’s language development by______ them. 

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.

By adopting a few simple techniques, parents who read to their children can considerably increase their children’s language development. It is surprising, but true. How parents talk to their children makes a big difference in the children’s language development. If a parent encourages the child to actively respond to what the parent is reading, the child’s language skills increase.

A study was done with two or three-year-old children and their parents. Half of the thirty children participants were in the experimental study; the other half acted as the control group. In the experimental group, the parents were given a two-hour training session in which they were taught to ask open-ended questions rather than yes-no questions. For example, the parent should ask, “What is the doggy doing?” rather than, “Is the doggy running away?” Experimental parents were also instructed how to expand on their children’s answer, how to suggest alternative possibilities, and how to praise correct answers.

At the beginning of the study, the children did not differ on levels of language development, but at the end of one month, the children in the experimental group were 5.5 months ahead of the control group on a test of verbal expression and vocabulary. Nine months later, the children in the experimental group still showed an advance of 6 months over the children in the control group.

What does the word “they” in the second paragraph refer 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.

By adopting a few simple techniques, parents who read to their children can considerably increase their children’s language development. It is surprising, but true. How parents talk to their children makes a big difference in the children’s language development. If a parent encourages the child to actively respond to what the parent is reading, the child’s language skills increase.

A study was done with two or three-year-old children and their parents. Half of the thirty children participants were in the experimental study; the other half acted as the control group. In the experimental group, the parents were given a two-hour training session in which they were taught to ask open-ended questions rather than yes-no questions. For example, the parent should ask, “What is the doggy doing?” rather than, “Is the doggy running away?” Experimental parents were also instructed how to expand on their children’s answer, how to suggest alternative possibilities, and how to praise correct answers.

At the beginning of the study, the children did not differ on levels of language development, but at the end of one month, the children in the experimental group were 5.5 months ahead of the control group on a test of verbal expression and vocabulary. Nine months later, the children in the experimental group still showed an advance of 6 months over the children in the control group.

During the training session, experimental parents were taught 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.

By adopting a few simple techniques, parents who read to their children can considerably increase their children’s language development. It is surprising, but true. How parents talk to their children makes a big difference in the children’s language development. If a parent encourages the child to actively respond to what the parent is reading, the child’s language skills increase.

A study was done with two or three-year-old children and their parents. Half of the thirty children participants were in the experimental study; the other half acted as the control group. In the experimental group, the parents were given a two-hour training session in which they were taught to ask open-ended questions rather than yes-no questions. For example, the parent should ask, “What is the doggy doing?” rather than, “Is the doggy running away?” Experimental parents were also instructed how to expand on their children’s answer, how to suggest alternative possibilities, and how to praise correct answers.

At the beginning of the study, the children did not differ on levels of language development, but at the end of one month, the children in the experimental group were 5.5 months ahead of the control group on a test of verbal expression and vocabulary. Nine months later, the children in the experimental group still showed an advance of 6 months over the children in the control group.

What was the major difference between the control group and the experimental one in the study?

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.

By adopting a few simple techniques, parents who read to their children can considerably increase their children’s language development. It is surprising, but true. How parents talk to their children makes a big difference in the children’s language development. If a parent encourages the child to actively respond to what the parent is reading, the child’s language skills increase.

A study was done with two or three-year-old children and their parents. Half of the thirty children participants were in the experimental study; the other half acted as the control group. In the experimental group, the parents were given a two-hour training session in which they were taught to ask open-ended questions rather than yes-no questions. For example, the parent should ask, “What is the doggy doing?” rather than, “Is the doggy running away?” Experimental parents were also instructed how to expand on their children’s answer, how to suggest alternative possibilities, and how to praise correct answers.

At the beginning of the study, the children did not differ on levels of language development, but at the end of one month, the children in the experimental group were 5.5 months ahead of the control group on a test of verbal expression and vocabulary. Nine months later, the children in the experimental group still showed an advance of 6 months over the children in the control group.

What conclusion can be drawn from this passage? 

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.

I’m sorry I can’t come out this weekend – I’m up to my ears in 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.

Workers are always advised to be cautious when entering and leaving the place due to a recent fire. 

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

Each of us must take ________ for our own actions

Her fiancé is said _______ from Harvard University five years ago. 

I can’t think of any possible _______ for his absence. 

Housewives find it easier to do domestic chores thanks to _______ invention of labour-saving devices. 

My supervisors is angry with me. I didn’t do all the work I _______ have done last week. 

Some films about violence have badly _______ children and teenagers. 

People should not have children unless they are _______ to being responsible parents. 

Ms. Brown asked me _______ in my class. 

With greatly increased workloads, everyone is _______ pressure now.

As there were too many participants at the seminar, the main speaker _______ them into four smaller groups for discussion.

Hurry up or you _______ the first lesson. 

Her first novel has been _______ acclaimed as a masterpiece.

I _______ along the street when I suddenly heard footsteps behind me. 

The families _______ houses were washed away by the tsunami were given temporary shelter in the school yard. 

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 CLOSET in meaning to the underlined part in each of the following questions.

Since her parents’ death, she has been brought up by her uncle. 

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

The natives were angry when foreigners came to their country and took over their land. 

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

: John and Alice are talking about going to the movie.

John: “I was wondering if you’d like to go to a movie tonight.”

Alice: “_______ What’s playing?”

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

This afternoon Hoa is visiting her home town.

Mark: “Don’t fail to send your family my regards.”

Hoa: “_______.” 

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.

Everyone wants to reduce pollution. But the pollution (30) ______ is as complicated as it is serious. It is complicated because much pollution is caused by things that benefit people. (31) ______, exhaust from automobiles causes a large percentage of air pollution. But the automobile provides transportation for millions of people. Factories discharge much of the material that pollutes the air and water but factories give (32) _______ to a large number of people.

Thus, to end or greatly reduce pollution immediately, people would have to (33) ______ using many things that benefit them. Most of the people do not want to do that, of course. But pollution can be gradually reduced in several ways. Scientists and engineers can work to find ways to lessen the amount of pollution that such things as automobiles and factories cause. Governments can pass and enforce laws (34) ______ require businesses and traffic to stop, or to cut down on certain polluting activities. 

Điền vào ô 30

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.

Everyone wants to reduce pollution. But the pollution (30) ______ is as complicated as it is serious. It is complicated because much pollution is caused by things that benefit people. (31) ______, exhaust from automobiles causes a large percentage of air pollution. But the automobile provides transportation for millions of people. Factories discharge much of the material that pollutes the air and water but factories give (32) _______ to a large number of people.

Thus, to end or greatly reduce pollution immediately, people would have to (33) ______ using many things that benefit them. Most of the people do not want to do that, of course. But pollution can be gradually reduced in several ways. Scientists and engineers can work to find ways to lessen the amount of pollution that such things as automobiles and factories cause. Governments can pass and enforce laws (34) ______ require businesses and traffic to stop, or to cut down on certain polluting activities.

Điền vào ô 31

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.

Everyone wants to reduce pollution. But the pollution (30) ______ is as complicated as it is serious. It is complicated because much pollution is caused by things that benefit people. (31) ______, exhaust from automobiles causes a large percentage of air pollution. But the automobile provides transportation for millions of people. Factories discharge much of the material that pollutes the air and water but factories give (32) _______ to a large number of people.

Thus, to end or greatly reduce pollution immediately, people would have to (33) ______ using many things that benefit them. Most of the people do not want to do that, of course. But pollution can be gradually reduced in several ways. Scientists and engineers can work to find ways to lessen the amount of pollution that such things as automobiles and factories cause. Governments can pass and enforce laws (34) ______ require businesses and traffic to stop, or to cut down on certain polluting activities.

Điền vào ô 32

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.

Everyone wants to reduce pollution. But the pollution (30) ______ is as complicated as it is serious. It is complicated because much pollution is caused by things that benefit people. (31) ______, exhaust from automobiles causes a large percentage of air pollution. But the automobile provides transportation for millions of people. Factories discharge much of the material that pollutes the air and water but factories give (32) _______ to a large number of people.

Thus, to end or greatly reduce pollution immediately, people would have to (33) ______ using many things that benefit them. Most of the people do not want to do that, of course. But pollution can be gradually reduced in several ways. Scientists and engineers can work to find ways to lessen the amount of pollution that such things as automobiles and factories cause. Governments can pass and enforce laws (34) ______ require businesses and traffic to stop, or to cut down on certain polluting activities. 

Điền vào ô 33

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.

Everyone wants to reduce pollution. But the pollution (30) ______ is as complicated as it is serious. It is complicated because much pollution is caused by things that benefit people. (31) ______, exhaust from automobiles causes a large percentage of air pollution. But the automobile provides transportation for millions of people. Factories discharge much of the material that pollutes the air and water but factories give (32) _______ to a large number of people.

Thus, to end or greatly reduce pollution immediately, people would have to (33) ______ using many things that benefit them. Most of the people do not want to do that, of course. But pollution can be gradually reduced in several ways. Scientists and engineers can work to find ways to lessen the amount of pollution that such things as automobiles and factories cause. Governments can pass and enforce laws (34) ______ require businesses and traffic to stop, or to cut down on certain polluting activities. 

Điền vào ô 34

Mark the letter A, B, C or D on your answer sheet to indicate the sentence that best joins each of the following pairs of sentences in each of the following questions.

The basketball team knew they lost the match. They soon started to blame each other.

Mark the letter A, B, C or D on your answer sheet to indicate the sentence that best joins each of the following pairs of sentences in each of the following questions. 

Crazianna is a big country. Unfortunately, it has never received respect from its neighbours.

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

To attract someone’s attention we can use either verbal and non-verbal forms of communication. 

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

The assumption that smoking has bad effects on our health have been proved. 

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

Dogs that are trained to lead the blind must be loyalty, intelligent and calm.

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

“No, it’s not true. I didn’t steal the money!” Jean said.

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

It is not until a Vietnamese girl getting 18 years old that she is allowed to get married legally. 

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

It is over twenty years since I last got in touch with them. 

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.

The elements other than hydrogen and helium exist in such small quantities that it is accurate to say that the universe is somewhat more than 25 percent helium by weight and somewhat less than 75 percent hydrogen.

Astronomers have measured the abundance of helium throughout our galaxy and in other galaxies as well. Helium has been found in old stars, in relatively young ones, in interstellar gas, and in the distant objects known as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fall on the earth (cosmic rays are not really a form of radiation; they consist of rapidly moving particles of numerous different kinds). It doesn’t seem to make very much difference where the helium is found. Its relative abundance never seems to vary much. In some places, there may be slightly more of it; in others, slightly less, but the ratio of helium to hydrogen nuclei always remains about the same.

Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce. However, the amount of helium that could have been produced in this manner can be calculated, and it turns out to be no more than a few percent. The universe has not existed long enough for this figure to be significant greater. Consequently, if the universe is somewhat more than 25 percent helium now, then it must have been about 25 percent helium at a time near the beginning.

However, when the universe was less than one minute old, no helium could have existed. Calculations indicate that before this time temperature were too high and particles of matter were moving around much too rapidly. It was only after the one-minute point that helium could exist. By this time, the universe had cooled so sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formations of helium went on for only relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased.

What does the passage mainly explain? 

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.

The elements other than hydrogen and helium exist in such small quantities that it is accurate to say that the universe is somewhat more than 25 percent helium by weight and somewhat less than 75 percent hydrogen.

Astronomers have measured the abundance of helium throughout our galaxy and in other galaxies as well. Helium has been found in old stars, in relatively young ones, in interstellar gas, and in the distant objects known as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fall on the earth (cosmic rays are not really a form of radiation; they consist of rapidly moving particles of numerous different kinds). It doesn’t seem to make very much difference where the helium is found. Its relative abundance never seems to vary much. In some places, there may be slightly more of it; in others, slightly less, but the ratio of helium to hydrogen nuclei always remains about the same.

Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce. However, the amount of helium that could have been produced in this manner can be calculated, and it turns out to be no more than a few percent. The universe has not existed long enough for this figure to be significant greater. Consequently, if the universe is somewhat more than 25 percent helium now, then it must have been about 25 percent helium at a time near the beginning.

However, when the universe was less than one minute old, no helium could have existed. Calculations indicate that before this time temperature were too high and particles of matter were moving around much too rapidly. It was only after the one-minute point that helium could exist. By this time, the universe had cooled so sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formations of helium went on for only relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased.

According to the passage, helium 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.

The elements other than hydrogen and helium exist in such small quantities that it is accurate to say that the universe is somewhat more than 25 percent helium by weight and somewhat less than 75 percent hydrogen.

Astronomers have measured the abundance of helium throughout our galaxy and in other galaxies as well. Helium has been found in old stars, in relatively young ones, in interstellar gas, and in the distant objects known as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fall on the earth (cosmic rays are not really a form of radiation; they consist of rapidly moving particles of numerous different kinds). It doesn’t seem to make very much difference where the helium is found. Its relative abundance never seems to vary much. In some places, there may be slightly more of it; in others, slightly less, but the ratio of helium to hydrogen nuclei always remains about the same.

Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce. However, the amount of helium that could have been produced in this manner can be calculated, and it turns out to be no more than a few percent. The universe has not existed long enough for this figure to be significant greater. Consequently, if the universe is somewhat more than 25 percent helium now, then it must have been about 25 percent helium at a time near the beginning.

However, when the universe was less than one minute old, no helium could have existed. Calculations indicate that before this time temperature were too high and particles of matter were moving around much too rapidly. It was only after the one-minute point that helium could exist. By this time, the universe had cooled so sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formations of helium went on for only relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased.

The word "constituents" 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.

The elements other than hydrogen and helium exist in such small quantities that it is accurate to say that the universe is somewhat more than 25 percent helium by weight and somewhat less than 75 percent hydrogen.

Astronomers have measured the abundance of helium throughout our galaxy and in other galaxies as well. Helium has been found in old stars, in relatively young ones, in interstellar gas, and in the distant objects known as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fall on the earth (cosmic rays are not really a form of radiation; they consist of rapidly moving particles of numerous different kinds). It doesn’t seem to make very much difference where the helium is found. Its relative abundance never seems to vary much. In some places, there may be slightly more of it; in others, slightly less, but the ratio of helium to hydrogen nuclei always remains about the same.

Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce. However, the amount of helium that could have been produced in this manner can be calculated, and it turns out to be no more than a few percent. The universe has not existed long enough for this figure to be significant greater. Consequently, if the universe is somewhat more than 25 percent helium now, then it must have been about 25 percent helium at a time near the beginning.

However, when the universe was less than one minute old, no helium could have existed. Calculations indicate that before this time temperature were too high and particles of matter were moving around much too rapidly. It was only after the one-minute point that helium could exist. By this time, the universe had cooled so sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formations of helium went on for only relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased.

Why does the author mention "cosmic rays"?

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.

The elements other than hydrogen and helium exist in such small quantities that it is accurate to say that the universe is somewhat more than 25 percent helium by weight and somewhat less than 75 percent hydrogen.

Astronomers have measured the abundance of helium throughout our galaxy and in other galaxies as well. Helium has been found in old stars, in relatively young ones, in interstellar gas, and in the distant objects known as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fall on the earth (cosmic rays are not really a form of radiation; they consist of rapidly moving particles of numerous different kinds). It doesn’t seem to make very much difference where the helium is found. Its relative abundance never seems to vary much. In some places, there may be slightly more of it; in others, slightly less, but the ratio of helium to hydrogen nuclei always remains about the same.

Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce. However, the amount of helium that could have been produced in this manner can be calculated, and it turns out to be no more than a few percent. The universe has not existed long enough for this figure to be significant greater. Consequently, if the universe is somewhat more than 25 percent helium now, then it must have been about 25 percent helium at a time near the beginning.

However, when the universe was less than one minute old, no helium could have existed. Calculations indicate that before this time temperature were too high and particles of matter were moving around much too rapidly. It was only after the one-minute point that helium could exist. By this time, the universe had cooled so sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formations of helium went on for only relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased.

The word "they" refers 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.

The elements other than hydrogen and helium exist in such small quantities that it is accurate to say that the universe is somewhat more than 25 percent helium by weight and somewhat less than 75 percent hydrogen.

Astronomers have measured the abundance of helium throughout our galaxy and in other galaxies as well. Helium has been found in old stars, in relatively young ones, in interstellar gas, and in the distant objects known as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fall on the earth (cosmic rays are not really a form of radiation; they consist of rapidly moving particles of numerous different kinds). It doesn’t seem to make very much difference where the helium is found. Its relative abundance never seems to vary much. In some places, there may be slightly more of it; in others, slightly less, but the ratio of helium to hydrogen nuclei always remains about the same.

Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce. However, the amount of helium that could have been produced in this manner can be calculated, and it turns out to be no more than a few percent. The universe has not existed long enough for this figure to be significant greater. Consequently, if the universe is somewhat more than 25 percent helium now, then it must have been about 25 percent helium at a time near the beginning.

However, when the universe was less than one minute old, no helium could have existed. Calculations indicate that before this time temperature were too high and particles of matter were moving around much too rapidly. It was only after the one-minute point that helium could exist. By this time, the universe had cooled so sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formations of helium went on for only relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased.

The word "vary" 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.

The elements other than hydrogen and helium exist in such small quantities that it is accurate to say that the universe is somewhat more than 25 percent helium by weight and somewhat less than 75 percent hydrogen.

Astronomers have measured the abundance of helium throughout our galaxy and in other galaxies as well. Helium has been found in old stars, in relatively young ones, in interstellar gas, and in the distant objects known as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fall on the earth (cosmic rays are not really a form of radiation; they consist of rapidly moving particles of numerous different kinds). It doesn’t seem to make very much difference where the helium is found. Its relative abundance never seems to vary much. In some places, there may be slightly more of it; in others, slightly less, but the ratio of helium to hydrogen nuclei always remains about the same.

Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce. However, the amount of helium that could have been produced in this manner can be calculated, and it turns out to be no more than a few percent. The universe has not existed long enough for this figure to be significant greater. Consequently, if the universe is somewhat more than 25 percent helium now, then it must have been about 25 percent helium at a time near the beginning.

However, when the universe was less than one minute old, no helium could have existed. Calculations indicate that before this time temperature were too high and particles of matter were moving around much too rapidly. It was only after the one-minute point that helium could exist. By this time, the universe had cooled so sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formations of helium went on for only relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased.

The creation of helium within stars ______ 

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.

The elements other than hydrogen and helium exist in such small quantities that it is accurate to say that the universe is somewhat more than 25 percent helium by weight and somewhat less than 75 percent hydrogen.

Astronomers have measured the abundance of helium throughout our galaxy and in other galaxies as well. Helium has been found in old stars, in relatively young ones, in interstellar gas, and in the distant objects known as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fall on the earth (cosmic rays are not really a form of radiation; they consist of rapidly moving particles of numerous different kinds). It doesn’t seem to make very much difference where the helium is found. Its relative abundance never seems to vary much. In some places, there may be slightly more of it; in others, slightly less, but the ratio of helium to hydrogen nuclei always remains about the same.

Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce. However, the amount of helium that could have been produced in this manner can be calculated, and it turns out to be no more than a few percent. The universe has not existed long enough for this figure to be significant greater. Consequently, if the universe is somewhat more than 25 percent helium now, then it must have been about 25 percent helium at a time near the beginning.

However, when the universe was less than one minute old, no helium could have existed. Calculations indicate that before this time temperature were too high and particles of matter were moving around much too rapidly. It was only after the one-minute point that helium could exist. By this time, the universe had cooled so sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formations of helium went on for only relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased.

Most of the helium in the universe was formed ______