题目内容
14.If a diver surfaces(浮出水面) too quickly,he may suffer the bends(减压病).Nitrogen (氮) dissolved (溶解) in his blood is suddenly liberated(释放)by the reduction of pressure.The consequence,if the bubbles (气泡) accumulate in a joint,is sharp pain and a bent body-thus the name.If the bubbles form in his lungs or his brain,the consequence can be death.Other air-breathing animals also suffer this decompression (减压) sickness if they surface too fast:whales,for example.And so,long ago,did ichthyosaurs(鱼龙).That these ancient sea animals got the bends can be seen from their bones.If bubbles of nitrogen form inside the bone they can cut off its blood supply.This kills the cells in the bone,and consequently weakens it,sometimes to the point of collapse.Fossil (化石) bones that have caved in on themselves are thus a sign that the animal once had the bends.
Bruce Rothschild of the University of Kansas knew all this when he began a study of ichthyosaur bones to find out how widespread the problem was in the past.What he particularly wanted to investigate was how ichthyosaurs adapted to the problem of decompression over the 150million years.To this end,he and his colleagues traveled the world's natural-history museums,looking at hundreds of ichthyosaurs from the Triassic(三叠纪) period and from the later Jurassic(侏罗纪) and Cretaceous(白垩纪) periods.
When he started,he assumed that signs of the bends would be rarer in younger fossils,reflecting their gradual evolution(进化)of measures to deal with decompression.Instead,he was astonished to discover the opposite.More than 15% of Jurassic and Cretaceous ichthyosaurs had suffered the bends before they died,but not a single Triassic specimen (标本) showed evidence of that sort of injury.
If ichthyosaurs did evolve an anti-decompression means,they clearly did so quickly-and,most strangely,they lost it afterwards.But that is not what Dr Rothschild thinks happened.He suspects it was evolution in other animals that caused the change.
Whales that suffer the bends often do so because they have surfaced to escape a predator (捕食动物) such as a large shark.One of the features of Jurassic oceans was an abundance of large sharks and crocodiles,both of which were fond of ichthyosaur lunches.Triassic oceans,by contrast,were mercifully shark-and crocodile-free.In the Triassic,then,ichthyosaurs were top of the food chain.In the Jurassic and Cretaceous,they were prey (猎物) as well as predator-and often had to make a speedy exit as a result.
58.Which of the following is a typical symptom of the bends?A
A.A twisted body.
B.A gradual decrease in blood supply.
C.A sudden release of nitrogen in blood.
D.A drop in blood pressure.
59.The purpose of Rothschild's study is to seeB.
A.how often ichthyosaurs caught the bends
B.how ichthyosaurs adapted to decompression
C.why ichthyosaurs bent their bodies
D.when ichthyosaurs broke their bones
60.Rothschild's finding stated in Paragraph 4C.
A.confirmed his assumption
B.speeded up his research process
C.disagreed with his assumption
D.changed his research objectives
61.Rothschild might have concluded that ichthyosaursA.
A.failed to evolve an anti-decompression means
B.gradually developed measures against the bends
C.died out because of large sharks and crocodiles
D.evolved an anti-decompression means but soon lost it.
分析 科普知识类文章.文章主要介绍Rothschild教授关于鱼龙类生物在近1亿5千万年里如何适应减压问题的研究.在开始研究时,他原本认为年轻化石里弯曲的迹象会比老化石里的少,因为这标志着鱼龙类生物逐渐进化出反减压器官,然而他的研究结果得出相反的结论.
解答 58-61 ABCA
58.选A 细节理解题.第一段第三句提到遭遇bend的症状是"sharp pain and a bent body",此处bent等于twisted,意为"扭曲的,弯曲的".故答案选A.
59.选B 细节理解题.根据第三段第二句"What he particularly wanted to investigate was how ichthyosaurs adapted to the problem of decompression over the 150million years.."可知Rothschild教授的研究目的是如何适应减压问题,答案为B.
60.选C 细节理解题.根据第四段第二句"Instead,he was astonished to discover the opposite."可知研究结果与他原本的假设相反,因此答案为C.
61.选A 推理判断题.根据文章倒数第二段第一句If ichthyosaurs did evolve an anti-decompression means,they clearly did so quickly-and,most strangely,they lost it afterwards.可以推断出答案.Rothschild可能已经得出结论:鱼龙类生物未能进化出反减压器官.
点评 做阅读时经常犯错的主要原因是,仅凭读过文章后残留在脑海中的一丝印象来勾选答案,这样便很容易掉入出题人故意设布下的题目陷阱.所谓阅读理解,对于题目的理解一定要忠实于原文,因此,每一道题都应该与原文作全面的对比与核查,再得出答案.也就是说,阅读理解的每一道题目,在原文都应该有明确的出处,我们把这一出处叫做原文相关句,(1)排除与原文相关句主题不一致的选项(2)排除与原文相关句态度相反的选项 (3)排除用于过于极端或负面的选项(4)注意结合文章主旨和主题去排除.

---Couldn't be worse.Stuck in the mud,the car ______ not move,however hard we pushed it.( )
A. | could | B. | would | C. | should | D. | might |
A. | three times as likely | B. | as likely three times | ||
C. | three times more likely | D. | more likely three times |