Question

    A black hole is created when a large star burns out. Like our sun, stars are unbelievably hot furnaces(熔炉)that burn their own matter as fuel. When most of the fuel is used up, the star begins to die.

The death of a star is not a quiet event. First there is a huge explosion. As its outer layer is blasted off into space, the dying star shines as brightly as a billion suns.

After the explosion gravity pulls in what's left of the star. As the outside of the star sinks toward the center, the star gets smaller and smaller. The material the star is made of becomes tightly packed together. A star is so dense that a teaspoon of matter from it weighs billion of pounds.

The more the star shrinks, the stronger the gravity inside it becomes. Soon the star is very tiny, and the gravity pulling it in is unbelievably strong. In fact, the gravity is so strong that it even pulls light into the star! Since all the light is pulled in, none can flee. The star becomes black when there is no light. Then a black hole is born!

That's what we know about black holes. What we don't know is this: What happens inside a black hole after the star has been squeezed into a tiny ball? Does it keep getting smaller and smaller forever? Such a possibility is hard to imagine.

But if the black hole doesn't keep shrinking, what happens to it? Some scientists think black holes are like doorways to another world. They say that as the star disappears from our universe, it goes into another universe. In other words a black hole in our universe could turn into a “white hole” in a different universe. As the black hole swallows light, the white hole shines brightly-somewhere else. But where? A different place, perhaps, or a different time-many years in the past or future.

Could you travel through a black hole? Right now, no. Nothing we know of could go into a black hole without being crushed. So far the time being, black holes must remain a mystery.

Black holes are a mystery-but that hasn't stopped scientists from dreaming about them. One scientist suggested that in the future we might make use of the power of black holes. They would supply all of Earth's energy needs, with plenty to spare. Another scientist wondered if a black hole could some day be used to swallow earthly waste-a sort of huge waste disposal(处理)in the sky!

1.When the star begins to die, .

A.there is no fuel left in it

B.its outer layer goes into space first

C.it will explode and then become smaller

D.it doesn't give off light any longer

2.Which of the following doesn't help produce a black hole?

A.The star becomes very tiny and dense.

B.The light can't go out of the star.

C.The gravity inside the star is very strong.

D.The dying star shines very brightly.

3.What can we know from the passage?

A.A star will blast and die when it lacks fuel to support its burning.

B.A black hole can swallow everything because it becomes smaller all the time.

C.Man can never travel through a black hole but can make use of its power.

D.Scientists have found that a black hole goes into another universe and becomes a white hole.

4.What's the best title for this passage?

A.A New Scientific Discovery: Black Holes

B.How Do Black Holes Come into Being?

C.What Are Black Holes?

D.Travel Through A Black Hole

Answer

1.C

2.D

3.A

4.B

【解析】

本文是一篇说明文。文章阐述了黑洞形成的原因和经过。

1.细节理解题。文章第一、二、三段提到，当一个星体的大部分能量耗尽，它就开始走向衰落死亡，首先是爆炸，由于爆炸，外层物质被抛散到太空中，并且发出非常耀眼的光线，然后它会慢慢向中心塌陷变小。因此，当一个星体死亡时，它会发生爆炸并变得更小。故选C。

2.细节理解题。从第四段The more the star shrinks, the stronger the gravity inside it becomes. Soon the star is very tiny, and the gravity pulling it in is unbelievably strong. In fact, the gravity is so strong that it even pulls light into the star! 可以看出由于引力的加大，形体不断收缩，变得很小，引力大到难以置信，光都被拉入到星体内部，因此A、B、C都是黑洞形成的因素之一，根据The star becomes black when there is no light.一句可知D选项错误。故选D。

3.推理判断题。从文章可知，星体燃烧的大部分能量之后，就开始死亡，并首先产生爆炸，故A正确。B的前半句正确，但黑洞能吞噬一切的原因是因为密度大，引力大，而不是因为黑洞一直在变小。C错误，因为文章只说目前穿越黑洞不可能，没有说永远不可能，而且我们也还不能利用黑洞的能力。D答案只是科学家的猜测，并不属实，而且句子本身也有错误，不是黑洞跑去了另一个宇宙，成为白洞，而是有可能在这个宇宙产生一个黑洞，相应的可能在另一个宇宙就会出现一个相反的白洞。故选A。

4.主旨大意题。文章的首句和全文都可以看出，文章主要内容是黑洞是如何形成的。选项B. How Do Black Holes Come into Being?（黑洞是怎样形成的？）为最佳标题。故选B。