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?

The company managed to beat the ____________on delivering its new system.

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.

Everyone thought she would accept the offer. ____________, she turned it down immediately.

There is still widespread____________against older people in the job market.

It was hard to____________the temptation to watch the late-night show even though I was so tired then.

I don’t know much about computer, so I asked the assistant for____________advice.

I ran in a marathon last week, but I was not fit enough. I____________after 15 kilometres.

The children were made____________up the mess they had left before they could watch TV.

You should know that everyone in this office____________busy planning the dance for a week.

Women have proved repeatedly that they are equal and often superior____________men in almost every field.

I wish I____________able to accept that role, but I was preparing for another play at the time.

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.

I would have cooked something special if I____________you were coming.

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: “____________”

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.