PASSAGE 04

🚩 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 1 to 10.

The Sun today is a yellow dwarf star. It is fueled by thermonuclear reactions near its center that convert hydrogen to helium. The Sun has existed in its present state for about four billion six hundred million years and is thousands of times larger than the Earth.

By studing other stars, astronomers can predict what the rest of the Sun's life will be like. About five billion years from now, the core of the Sun will shrink and become hotter. The surface temperature will fall. The higher temperature of the center will increase the rate of the thermonuclear reaction. The outer regions of the Sun will expand approximately 35 million miles, about the distance to Mercury, which is the closest planet to the Sun. The Sun will then be a red giant star. Temperatures on the Earth will become too hight for life to exist

Once the sun has used up its thermonuclear energy as a red giant, it will begin to shrink. After it shrinks to the size of the Earth, it will become a white dwarf star. The Sun may throw off huge amounts of gases in violent eruptions called nova explosions as it changes from a red giant to a white dwarf.

After billions of years as a white dwarf, the Sun will have used up all its fuel and will have lost its heat. Such a star is called a black dwarf. After the Sun has become a black dwarf, the Earth will be dark and cold. If any atmosphere remains there, it will have frozen over the Earth's surface.

Vocabulary

• dwarf (adj): nhỏ xíu, nhỏ

• fuel (v): .....

Question 1: It can be inferred from the passage that the Sun __________

A. is approximately halfway through its life as a yellow dwarf star.

B. will continue to be a yellow dwarf for another 10 billion years

C. has been in existence for 10 billion years

D. is rapidly changing in size and brightness

Question 2: What will probably be the first stage of change for the Sun to become a red giant?

A. Its surface will become hotter and shrink

B. It will throw off huge amounts of gases.

C. Its central part will grow smaller and hotter

D. Its core will cool off and use less fuel

Question 3: When the Sun becomes a red giant, what will the atmosphere be like on the Earth?

A. It will be enveloped in the expanding surface of the sun.

B. It will become too hot for life to exist.

C. It will be almost destroyed by nova explosions

D. It will freeze and become solid

Question 4: When the Sun has used up its energy as red giant, it will ________.

A. get frozen

B. cease to exist

C. stop to expand

D. become smaller

Question 5: Large amounts of gases may be released from the Sun at the end of its life as a ________.

A. black dwarf

B. white dwarf

C. red giant

D. yellow dwarf

Question 6: As a white dwarf, the Sun will be ______.

A. the same size as the planet Mercury

B. around 35 million miles in diameter

C. a cool and habitable planet

D. thousands of times smaller than it is today

Question 7: The Sun will become a black dwarf when ___________.

A. the Sun moves nearer to the Earth

B. it has used up all its fuel as a white dwarf

C. the core of the Sun becomes hotter

D. the outer regions of the Sun expand

Question 8: The word "there" in the last sentence of paragraph 4 refers to __________.

A. the planet Mercury

B. the core of a black dwarf

C. our own planet

D. the outer surface of the Sun

Question 9: This passage is intended to ____________.

A. describe the changes that the Sun will go through

B. present a theory about red giant stars

C. alert people to the dangers posed by the Sun

D. discuss conditions on the Earth in the far future.

Question 10: The passage has probably been taken from ___________.

A. a scientific journal

B. a news report

C. a work of science fiction

D. a scientific chronicle