50 câu hỏi
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
theatre
thunder
therefore
throughout
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.
apologises
invites
roofs
certificates
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
sector
lawyer
workforce
prefer
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.
diversity
biography
biology
fundamental
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
I don’t know much about computer, so I asked the assistant for____________advice
a little
many
a few
a lot
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
You should know that everyone in this office____________busy planning the dance for a week
is
has been
are
have been
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.
The children were made____________up the mess they had left before they could watch TV
clear
to clear
clearing
cleared
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
Most headaches____________with aspirin unless they are too severe
can treat
can be treating
can be treated
can treats
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
I wish I____________able to accept that role, but I was preparing for another play at the time
were
was
had been
have been
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
Everyone thought she would accept the offer. ____________, she turned it down immediately
Therefore
Moreover
However
Hitherto
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 have cooked something special if I____________you were coming.
knew
know
have known
had known
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
Women have proved repeatedly that they are equal and often superior____________men in almost every field
to
than
as
over
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
There is still widespread____________against older people in the job market.
discriminate
discriminatory
discrimination
discriminating
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
The arrested man is suspected of____________government funds for himself.
robbing
appropriating
appreciating
confiscating
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
It was hard to____________the temptation to watch the late-night show even though I was so tired then
defy
resist
refuse
oppose
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
The company managed to beat the ____________on delivering its new system.
team
other
time
clock
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
Even though she had been studying hard, she had only a____________chance of passing the exam
slim
narrow
thin
light
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
I ran in a marathon last week, but I was not fit enough. I____________after 15 kilometres
dropped out
moved in
showed off
closed down
Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions
Keith had so interesting and creative plans that everyone wanted to work on his committee
wanted
plans
so interesting
on
Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions
Air pollution, together with littering, are causing many problems in our large, industrial world
in our large
with
many
are
Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions
A paragraph is a portion of a text consists of one or more sentences related to the same idea
sentences
consists of
to
A paragraph
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 questions
Greater use of public transport would cut the amount of pollution from cars.
Were more people to use public transport, cars would stop releasing exhaust into the atmosphere
If more people use public transport, it will cut the amount of pollution from cars
If public transport was widely used, people would no longer suffer from pollution from cars
If more people used public transport, there would be less pollution from cars
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 questions
Mark delayed writing the book until he had done a lot of research
Mark did a lot of research after he finished writing the book
It was only when Mark had written the book that he did a lot of research
Mark delayed writing the book as he had already done any research
Only after Mark had done a lot of research did he begin to write the book
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 questions
“Would you like to come out to dinner with me tonight, Jenny?” Paul said.
Paul suggested that Jenny go out to dinner with him that night
Paul insisted on Jenny going out to dinner with him that night
Paul invited Jenny to go out to dinner with him that night
Pau offered Jenny to go out to dinner with him that night
Mark the letter A, B, C or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions
Lee gave up her job. She planned to continue her education
Lee’s education was interrupted since she wanted to find a job
Lee gave up her job with the aim at continuing her education
Lee gave up her job in case she continued her education
Lee gave up her job with a view to continuing her education
Mark the letter A, B, C or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.
This is a rare opportunity. You should take advantage of it to get a better job.
You should take advantage of this rare opportunity, for which is to get a better job
This is a rare opportunity what you should take advantage of to get a better job
You should take advantage of this opportunity, that is rare to get a better job
This is a rare opportunity that you should take advantage of to get a better job
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
Mark and Anne are talking after the class.
Mark: “Guess what? I’ve been recruited to be a member of Green Dream Volunteer Group.”
Anne: “____________”
Good luck next time
That’s great! Congratulations
That’s the least thing I could do for you
It doesn’t make sense to me
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
Amy and Jacob are talking about the two-day excursion at the end of the school year. Amy: “You look so sad. ____________”
Jacob: “I couldn’t get my parents’ permission to stay the night away from home.”
Can you help me?
How do you deal with it?
What should I do
what’s the problem?
Mark the letter A, B, C, or D on your answer sheet to indicate the word or phrase that is CLOSEST in meaning to the underlined part in each of the following questions
It was late at night, the wind was howling and when she heard the knock on the door, she almost jumped out of her skin
was surprised
was asleep
was terrified
was delighted
Mark the letter A, B, C, or D on your answer sheet to indicate the word or phrase that is CLOSEST in meaning to the underlined part in each of the following questions
Wild animals use various methods to ward off predators and their natural enemies
rebel
befriend
deter
attack
Mark the letter A, B, C, or D on your answer sheet to indicate the word or phrase that is OPPOSITE in meaning to the underlined part in each of the following questions
We should grow more trees so that they can absorb more carbon dioxide from the atmosphere
take in
emit
consume
cut off
We have achieved considerable results in the economic field, such as high economic growth, stability and significant poverty alleviation over the past few years.
eradication
aggravation
prevention
reduction
Read the following passage and mark the letter A, B, C or Don your answer sheet to indicate the correct word for each of the blanks from 33 to 37.
Everyone wants to reduce pollution. But the pollution (33) ____________is as complicated as it is serious. It is complicated because much pollution is caused by things that benefit people. (34) ____________, 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 (35) ____________to a large number of people.
Thus, to end or greatly reduce pollution immediately, people would have to (36) ____________using many things that benefit them. Most 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 (37) ____________require businesses and traffic to stop, or to cut down on certain polluting activities
event
accident
work
problem
Read the following passage and mark the letter A, B, C or Don your answer sheet to indicate the correct word for each of the blanks from 33 to 37.
Everyone wants to reduce pollution. But the pollution (33) ____________is as complicated as it is serious. It is complicated because much pollution is caused by things that benefit people. (34) ____________, 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 (35) ____________to a large number of people. Thus, to end or greatly reduce pollution immediately, people would have to (36) ____________using many things that benefit them. Most 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 (37) ____________require businesses and traffic to stop, or to cut down on certain polluting activities
As a result
However
Therefore
For example
Read the following passage and mark the letter A, B, C or Don your answer sheet to indicate the correct word for each of the blanks from 33 to 37.
Everyone wants to reduce pollution. But the pollution (33) ____________is as complicated as it is serious. It is complicated because much pollution is caused by things that benefit people. (34) ____________, 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 (35) ____________to a large number of people.
Thus, to end or greatly reduce pollution immediately, people would have to (36) ____________using many things that benefit them. Most 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 (37) ____________require businesses and traffic to stop, or to cut down on certain polluting activities.
employed
employment
unemployed
unemployment
Read the following passage and mark the letter A, B, C or Don your answer sheet to indicate the correct word for each of the blanks from 33 to 37.
Everyone wants to reduce pollution. But the pollution (33) ____________is as complicated as it is serious. It is complicated because much pollution is caused by things that benefit people. (34) ____________, 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 (35) ____________to a large number of people.
Thus, to end or greatly reduce pollution immediately, people would have to (36) ____________using many things that benefit them. Most 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 (37) ____________require businesses and traffic to stop, or to cut down on certain polluting activities
start
stop
enjoy
continue
Read the following passage and mark the letter A, B, C or Don your answer sheet to indicate the correct word for each of the blanks from 33 to 37.
Everyone wants to reduce pollution. But the pollution (33) ____________is as complicated as it is serious. It is complicated because much pollution is caused by things that benefit people. (34) ____________, 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 (35) ____________to a large number of people.
Thus, to end or greatly reduce pollution immediately, people would have to (36) ____________using many things that benefit them. Most 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 (37) ____________require businesses and traffic to stop, or to cut down on certain polluting activities
whom
that
whose
who
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.
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
responding to
reading to
adopting
experimenting
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.
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?
Participants
Children
Questions
Parents
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.
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____________.
use yes-no questions
study many experiments
ask open-ended questions
give correct answers
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.
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
The number of participants
The books that were read
The age of the children
The training that parents received
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.
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?
Children who read actively always act six months earlier than those who don't
The more children read, the more intelligent they become
Two or three-year-old children can be taught to read actively
Children's language skills increase when they are required to respond actively
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 43 to 50.
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 significantly 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 temperatures 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
Why hydrogen is abundant
How stars produce energy
When most of the helium in the universe was formed
The difference between helium and hydrogen
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 43 to 50.
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 significantly 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 temperatures 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____________.
difficult to detect
the oldest element in the universe
the second-most abundant element in the universe
the most prevalent element in quasars
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 43 to 50.
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 significantly 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 temperatures 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____________.
causes
relatives
components
targets
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 43 to 50.
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 significantly 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 temperatures 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”?
To explain how the universe began
As an example of an unsolved astronomical puzzle
To explain the abundance of hydrogen in the universe
As part of a list of things containing helium
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 43 to 50.
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 significantly 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 temperatures 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____________
radiation
constituents
cosmic rays
particles
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 43 to 50.
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 significantly 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 temperatures 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____________.
include
mean
stretch
change
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 43 to 50.
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 significantly 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 temperatures 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____________.
cannot be measured
produces hydrogen as a by-product
produces energy
causes helium to be much more abundant in old stars than in young 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 from 43 to 50.
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 significantly 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 temperatures 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____________
in a very short time
in interstellar space
before most of the hydrogen
during the first minute of the universes existence