Black Holes

　　(1) Black holes can be best described as a sort of vacuum, sucking up everything in space.Scientists have discovered that black holes come from an explosion of huge stars. Stars that are near death can no longer bum due to loss of fuel, and because its temperature can no longer control the gravitational (重力的 ) force, hydrogen ends up putting pressure onto the star's surface until it suddenly explodes then collapses.

　　(2) Black holes come from stars that are made of hydrogen, other gases and a few metals. When these explode it can turn into a stellar-mass(恒星质量)black hole, which can only occur if the star is large enough (should be bigger than the sun) for the explosion to break it into pieces,and the gravity starts to compact every piece into the tiniest particle. Try to see and compare:if a star that's ten times the size of the sun end up being a black hole that's no longer than 70 kilometers, then the Earth would become black hole that's only a fraction of an inch!

　　(3) Objects that get sucked in a black hole will always remain there, never to break free. But remember that black holes can only gobble up (吞噬) objects within a specific distance to it. It's possible for a large star near the sun to become a black hole, but the sun will continue to stay in place. Orbits (轨道) do not change because the newly formed black hole contains exactly the same amount of mass as when it was a star, only this its mass is totally contracted that it can end up as no bigger than a state.

　　(4)So far, astronomers have figured out that black holes exist because of Albert Einstein's theory of relativity. In the end, through numerous studies, they have discovered that black holes truly exist. Since black holes trap light and do not give off light, it is not possible to detect black holes via a telescope. But astronomers continue to explore galaxies (银河系) , space and the solar system to understand how black holes. It is possible that black holes can exist for millions of years, and later contribute further process in galaxies, which can eventually lead to creation of new entities. Scientists also credit black holes as helpful in learning how galaxies began to form.

　　23"～26概括大意

　　23. Paragraph 1 __________

　　24. Paragraph 2 __________

　　25. Paragraph 3 __________

　　26. Paragraph 4 __________

　　A. Is there proof that black holes really exist?

　　B. What are different types of black holes?

　　C. How are black holes formed?

　　D. How were black holes named

　　E. What happens to the objects around a black hole?

　　F. What are black holes made of?.

　　27～30完成句子

　　27. Black holes are formed after__________.

　　28. When a large star explodes, the gravity compacts ever piece into __________.

　　29. A newly formed black hole and the star it comes from are of __________.

　　30. Albert Einstein's theory of relativity helps to prove __________.

　　A. the creation of new entities

　　B. an explosion of huge stars

　　C. the tiniest particle

　　D. the same amount of mass

　　E. the existence of black holes

　　F. a fraction of an inch

　　23.C。第一段没有主题句，通过第二句可知黑洞形成是由于巨大的星体爆炸，第三旬说明了巨大的星体是如何爆炸的，所以第一段讲的就是黑洞的形成过程，因此答案为C(黑洞是如何形成的)。

　　24.F。第二段首句是主题句，即“黑洞来自于那些由氢、其他气体以及一些金属组成的星体”，因而F选项(黑洞是由什么构成的)为正确答案。

　　25.E。第三段的主题句为首句，即“被黑洞吞噬的物体永远存在，永远不会逃逸出来”。但第二个句子是将but放在句首，所以重点就转向第二个句子，即“但是要记住黑洞只能吞噬与其保持特定距离的物体”，所以E(黑洞周围的物体会怎么样)为正确答案。

　　26.A。第四段的主题句是首句，即“到目前为止，天文学家根据爱因斯坦的相对论已经推断出黑洞的存在”，后面的句子都是有关天文学家对黑洞的研究，并且证明黑洞是真实存在的，所以A选项(有证据证明黑洞真实存在吗)为正确答案。

　　27.B。题干：黑洞是在__________之后形成的。利用题干的关键词black holes和form可以定位到第一段第二句，可知科学家发现黑洞源于巨大的星体爆炸，所以正确答案为B(巨大星体的爆炸)。

　　28.C。题干：当巨大的星体爆炸时，重力将爆炸物压缩成__________。利用题干的关键词explode，compact，gravity可以定位到第二段：“…，and the gravity starts to compact every piece into the tiniest particle.”可知重力把爆炸产生的物体压缩成颗粒。因此此处填“最微小的粒子”，所以正确答案为C(最微小的颗粒)。

　　29.D。题干：新形成的黑洞和产生黑洞的那个星体__________。利用题干关键词the newly formed black hole可以定位到文章第三段“the newly formed black hole contains exactly the same amount ofmass as when it was a star”，可知黑洞和形成黑洞的那个星体的质量相同，所以正确答案为D。

　　30.E。题干：爱因斯坦的相对论有助于证明__________。利用题干关键词Albert Einstein’s theory定位到文章第四段第一句，可知天文学家断定黑洞的存在是因为爱因斯坦的相对论，所以正确答案为E。

（编辑：何莹莹）