A.GOODS B.SUPPLIES C.PROVISIONS D.MATERIALS XVII. CHOOSE THE ITEM (...

10.A.goods B.supplies C.provisions D.materials

XVII. Choose the item (A, B, C or D) that best answers the question about the

assage:

The sun today is a yellow dwarf star. It is powered by thermonuclear reactions near its

center that change hydrogen into helium. The sun has existed in its present state for about

4 billion, 600 million years and is thousands of time greater than the earth.

By studying other stars, astronomers can predict what the rest of the sun’s life will be

like. About 5 billion years from now, the core of the sun will become smaller and hotter.

The surface temperature will fall. The higher temperature of the centre will increase the

rate of thermonuclear reactions. The outer regions of the sun will expand approximately

35 million miles, about the distance to Mercury, which is the closest planet to the

sunt.The sun will then be a red giant star. Temperatures on the earth will become too hot

for life to exist.

Once the sun has used up its thermonuclear energy as a red giant, it will begin to shrink.

After it becomes smaller 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.

I. What is the primary purpose of this passage?

A. To alert people to the dangers posed by the sun. B. To discuss conditions on earth in

the far future.

C. To present a theory about red giant stars. D. To describe changes that the sun

will go through.