共用题干 Black Holes1 Black holes can be best described as a sort of vacuum,suck...

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问题共用题干 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
burn 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 ihat 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 ends
up being a black hole that's no longer than 70 kilometers,then the Earth would become a 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.i1it 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 time its mass is totally contracted that it can end up as no bigger than a state.
4 Sofar,astronomers have figured out that black holes exist because of Albert Einstcin'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 nearly impossible to detect black holes via a telescope.But
astronomers continue to study galaxies（银河系）, space and the solar system to understand how black holes
might evolve.It is possible that black holes can exist for millions of years,and later contribute to a bigger
process in galaxies,which can eventually lead to creation of new entities（实体）.Scientists also credit black
holes as helpful in learning how galaxies began to form.

选项 When a large star explodes,the gravity compacts every piece into______. A:the existence of black holes B:the creation of new entities C:the same amount of mass D:an fraction of an inch E:a fraction of an inch F:the tiniest particle

答案 F

解析第一段描述了什么是黑洞，以及它产生的缘由―巨型恒星爆炸，并叙述了恒星爆炸的原因和简要过程。再看选项，只有F项符合题意。
第二段的主要内容是：恒星来自由氢气、其他气体和一些金属组成的恒星；当这些物质爆炸时，恒星就变成了质量与原先的恒星等同的黑洞，恒星的每个碎片都被重力压缩成极小的颗粒。观察选项，似乎E、F两项都可选，但一则上一小题只能选F项，二则此段虽也讲了黑洞是怎么形成的，但比较侧重黑洞形成过程中，原来的恒星变成极小的颗粒。由第三段最后一句也可知，这些颗粒的质量总和与原来的恒星一样，正是这些颗粒使黑洞有极大的吸附性，而成其为“黑洞”。因此，黑洞就是由这些极小却质量巨大、吸附性极强的颗粒构成的。故选E。
第三段描述了黑洞极大的吸附性，及其具有如此大的吸附性的原因。黑洞形成后，周围一定距离内的几乎一切东西都会被吞噬而难以逃脱，故选A。
第四段主要讲黑洞存在的依据及科学家们的研究和设想。故选B。
由第一段第二句“...black holes come from an explosion of huge stars.”可知答案。
由第二段第二句后半部分“...the gravity starts to compact every piece into the tiniestparticle”可知答案。
由第三段最后一句“…the newly formed black hole contains exactly the same amount of mass as when it was a star...”可知答案。
由第四段第一句话可知答案。

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共用题干 Black Holes1 Black holes can be best described as a sort of vacuum,suck...

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