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考研綜合演練與答案詳解（3）
Passage 3
What is a black hole? Well, it is difficult to answer this question, since the terms we would normally use to describe a scientific phenomenon are inadequate here. 1) __________________________________________________. A black hole exerts a strong gravitational pull and yet it has no matter. It is only space —— or so we think. How can this happen?
2) __________________________________________________. From earth, a supernova looks like a very bright light in the sky that shines even in the daytime. Supernova was reported by astronomers in the seventeenth and eighteenth centuries. Some people think that the Star of Bethlehem could have been a supernova. The collapse of a star may produce a White Dwarf of a neutron star —— a star, whose matter is so dense that it continually shrinks by the force of its own gravity. But if the star is very large (much bigger than our sun), this process of shrinking may be so intense that a black hole results. 3) __________________________________________________. Amy matter near the black hole is sucked in. It is impossible to say what happens inside a black hole. Scientists have called the boundary area around the hole the “event horizon”. We know nothing about events that happen once objects pass this boundary. But in theory, matter must behave very differently inside the hole.
4) __________________________________________________. Our space and time laws don't seem to apply to objects in the area of a black hole. Einstein claimed that matter and energy are interchangeable, so that there is no “absolute” time and space. There are no constants at all, and measurements of time and space depend on the position of the observer. They are relative. We do not yet fully understand the implications of the relativity theory; but it is interesting that Einstein's theory provided a basis for the idea of black holes before astronomers started to find some evidence for their existence. It is only recently that astronomers have begun specific research into black holes. 5 ) __________________________________________________.
The most convincing evidence of black holes comes from research into binary star systems. Binary stars, as their name suggests, are twin stars whose position in space affects each other. In some binary systems, astronomers have shown that there is an invisible companion star, a “partner” to the one that we can see in the sky. Matter from the one that we can see is being pulled towards the companion star. Should this invisible star, which exerts such a great force be a black hole? Astronomers have evidence of a few other stars too, which might have black holes as companions.
The story of black holes is just beginning. Speculations about them are endless.
[A] For example, if a man fell into a black hole, he would think that he reached the center of it very quickly. However, an observer at the event horizon would think that the man never reached the center at all.
[B] There might be a massive black hole at the center of our galaxy swallowing up stars at a very rapid rate.
[C] The theory is that some stars explode when their density increases to a particular point; they collapse and sometimes a supernova occurs.
[D] In August 1977, a satellite was launched to gather data about the 10 million black holes that are thought to be in the Milky Way. And astronomers are planning a new observatory to study the individual exploding stars believed to be black holes.
[E] Imagine the earth reduced to the size of a marble, but still having the same mass and a strong gravitational pull, and you have some idea of the force of a black hole.
[F] The theory of black holes in space is accepted by many serious. Scientists and astronomers. They show us a world that operates in a totally different way from our own and they question our most basic experience of space and time.
[G] Astronomers and scientists think that a black hole is a region of space ( not a thing) into which matters have fallen and from which nothing can escape - not even light. So we can't see a black hole.
【文章大意及結(jié)構(gòu)分析】
本文是一篇關(guān)于“黑洞”的科普性文章。文章開頭先給黑洞下了定義，即“黑洞是一個(gè)任何物體，包括光線一旦掉入就無法逃脫的地區(qū)”。第二段開始講黑洞的形成，首先從理論上進(jìn)行闡述，并以地球?yàn)槔齺韼椭x者進(jìn)行理解，即黑洞是星體達(dá)到一定密度后本身會在自己的引力作用下不斷縮小，此過程會強(qiáng)烈到產(chǎn)生黑洞。然后介紹有關(guān)黑洞周圍的“視界”和愛因斯坦的相對論對黑洞研究的幫助。文中指出科學(xué)家在對黑洞的研究方面已經(jīng)取得了成就。最后講人們對黑洞的研究永無止境。
從體裁上，本篇屬于“觀點(diǎn)論證型”說明性論述文，文章主要采用“提出理論—做出定義—舉例說明”的行文格式，講述了天文學(xué)上的黑洞理論。文章的第一段提出黑洞這一理論并給出其定義。第二段到第四段是以超新星和雙星系統(tǒng)為例證，從兩個(gè)方面對黑洞的形成進(jìn)行了理論上的論述。最后一段講黑洞的故事才剛剛開始。關(guān)于它們的設(shè)想是永無止境的。
【解題思路與答案詳解】
1) 【答案】[G]。本題在文章第一自然段的中間。我們要根據(jù)它的前后文義來做出選擇。文章開始提出問題：什么是黑洞?接著說這個(gè)問題難以回答，因?yàn)槲覀兺ǔＫ鶕碛械脑~匯不足以描繪這一科學(xué)現(xiàn)象。接著就是空白，空白后面又說，黑洞會產(chǎn)生強(qiáng)大的引力，但它卻沒有物質(zhì)，只有空間。這是對黑洞的進(jìn)一步解釋。顯而易見，空白處應(yīng)該是對“什么是黑洞?”這一問題的回答。這類科普文章常常是先提出問題，然后給出定義或答案，再做進(jìn)一步闡述。選項(xiàng)[G]符合這種順承關(guān)系，它是從科學(xué)家和天文學(xué)家的角度給出看法，正與此相符合，所以選項(xiàng)[G]是正確答案。
2) 【答案】[C]。本題在文章第二自然段的開始。在上一段提出了黑洞是如何產(chǎn)生的問題。本段是上一段的延續(xù)和擴(kuò)展，要在理論上對黑洞進(jìn)行解釋。再看問題后面的內(nèi)容，講到超新星：From earth, a supernova looks like a very bright light in the sky that shines even in the daytime.（從地球上看，一個(gè)超新星就像天空中一束明亮的光，有時(shí)甚至在白天也很耀眼）。這正是選項(xiàng)[C]內(nèi)容的延續(xù)和擴(kuò)展，兩者正好形成順承關(guān)系。所以，選項(xiàng)[C]是正確答案。
3) 【答案】[E]。本題在第二自然段的中間。要根據(jù)上下文來判斷其內(nèi)容，而后進(jìn)行選擇。上文提到了黑洞的產(chǎn)生，下文提到了靠近黑洞的任何物質(zhì)都被吸進(jìn)去，可以推斷空白處還應(yīng)該是與黑洞的吸力有關(guān)的內(nèi)容。這樣，行文才連貫，結(jié)構(gòu)才嚴(yán)謹(jǐn)，意義才流暢。選項(xiàng)[E]講：設(shè)想一下地球縮小到彈子球的大小，但仍然有同樣的質(zhì)量和引力，你就能對黑洞的力量有所了解了（Imagine the earth reduced to the size of a marble，but still having the same mass and a strong gravitational pull，and you will have some idea of the force of a black hole．）。正符合這些要求，所以選項(xiàng)[E]是正確答案。
4) 【答案】[A]。本題在一個(gè)段落的開始。上一段最后講到：物體一旦跨過邊緣之后，我們就不知道發(fā)生了什么。但從理論上講，物質(zhì)在黑洞內(nèi)的表現(xiàn)會明顯不同（We know nothing about events that happen once objects pass this boundary. But in theory, matter must behave very differently inside the hole.）�？瞻缀竺娴膬�(nèi)容是：我們的“時(shí)間和空間法則”并不適合于黑洞內(nèi)的物質(zhì)。并進(jìn)一步用Einstein的相對論來證明這一點(diǎn)。由此推斷，空白處應(yīng)該用一個(gè)通俗易懂的例子來進(jìn)一步解釋這些理論。選項(xiàng)[A]就是以一個(gè)進(jìn)入黑洞的人和一個(gè)觀察者的不同感覺來說明這一點(diǎn)。選項(xiàng)[A]與前面的內(nèi)容形成例證關(guān)系。前面提出觀點(diǎn)，接著給出論證。所以，[A]是正確答案。
5) 【答案】[D]。本題要與上一題結(jié)合起來解答，因?yàn)楸绢}在上題所在段落的結(jié)尾處。該段以論證說明我們的時(shí)空法則不適合于黑洞里的物質(zhì)，接著又講到：愛因斯坦的理論在天文學(xué)家拿出證據(jù)證明黑洞的存在之前就提供了理論基礎(chǔ)。只是最近天文學(xué)家才開始對黑洞進(jìn)行具體研究（but it is interesting that Einstein's theory provided a basis for the idea of black holes before astronomers started to find some evidence for their existence. It is only recently that astronomers have begun specific research into black holes.）。根據(jù)上文的內(nèi)容，我們可以推斷，下面應(yīng)該以具體的事實(shí)或例證來說明最近天文學(xué)家對活動(dòng)做了哪些具體的研究。選項(xiàng)[D]正是這樣的內(nèi)容：“1977年發(fā)射的一顆人造衛(wèi)星收集到了關(guān)于銀河系一千萬個(gè)黑洞的數(shù)據(jù)。天文學(xué)家正在計(jì)劃建造一個(gè)新的天文站來觀測被認(rèn)為是黑洞的單個(gè)爆炸星體�！边x項(xiàng)[D]與前文有著論證關(guān)系，銜接得非常自然。所以，選項(xiàng)[D]是正確答案。
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