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1、 为了帮助大家高效备考托福, 为大家带来托福 TPO42 阅读 Passage2 原文文本+题目+答案 解析,希望对大家备考有所帮助。 Explaining Dinosaur Extinction Dinosaurs rapidly became extinct about 65 million years ago as part of a mass extinction known as the K-T event,because it is associated with a geological signature known as the K-T boundary,usually a
2、thin band of sedimentation found in various parts of the world(K is the traditional abbreviation for the Cretaceous,derived from the German name Kreidezeit).Many explanations have been proposed for why dinosaurs became extinct.For example,some have blamed dinosaur extinction on the development of fl
3、owering plants,which were supposedly more difficult to digest and could have caused constipation or indigestionexcept that flowering plants first evolved in the Early Cretaceous,about 60 million years before the dinosaurs died out.In fact,several scientists have suggested that the duckbill dinosaurs
4、 and homed dinosaurs,with their complex battery of grinding teeth,evolved to exploit this new resource of rapidly growing flowering plants Others have blamed extinction on competition from the mammals,which allegedly ate all the dinosaur eggsexcept that mammals and dinosaurs appeared at the same tim
5、e in the Late Triassic,about 190 million years ago,and there is no reason to believe that mammals suddenly acquired a taste for dinosaur eggs after 120 million years of coexistence Some explanations(such as the one stating that dinosaurs all died of diseases)fail because there is no way to scientifi
6、cally test them,and they cannot move beyond the realm of speculation and guesswork. This focus on explaining dinosaur extinction misses an important point the extinction at the end of the Cretaceous was a global event that killed off organisms up and down the food chain.It wiped out many kinds of pl
7、ankton in the ocean and many marine organisms that lived on the plankton at the base of the food chain.These included a variety of clams and snails,and especially the ammonites,a group of shelled squidlike creatures that dominated the Mesozoic seas and had survived many previous mass extinctions.The
8、 K-T event marked the end of the marine reptiles,such as the mosasaurs and the plesiosaurs,which were the largest creatures that had ever lived in the seas and which ruled the seas long before whales evolved.On land,there was also a crisis among the land plants,in addition to the disappearance of di
9、nosaurs.So any event that can explain the destruction of the base of the food chain(plankton in the ocean,plants on land)can better explain what happened to organisms at the top of the food chain,such as the dinosaurs.By contrast,any explanation that focuses strictly on the dinosaurs completely miss
10、es the point The Cretaceous extinctions were a global phenomenon,and dinosaurs were just a part of a bigger picture. According to one theory,the Age of Dinosaurs ended suddenly 65 million years ago when a giant rock from space plummeted to Earth.Estimated to be ten to fifteen kilometers in diameter,
11、this bolide(either a comet or an asteroid)was traveling at cosmic speeds of 20-70 kilometers per second,or 45,000-156,000 miles per hour.Such a huge mass traveling at such tremendous speeds carries an enormous amount of energy.When the bolide struck this energy was released and generated a huge shoc
12、k wave that leveled everything for thousands of kilometers around the impact and caused most of the landscape to burst into flames.The bolide struck an area of the Yucatan Peninsula of Mexico known as Chicxulub,excavating a crater 15-20 kilometers deep and at least 170 kilometers in diameter.The imp
13、act displaced huge volumes of seawater,causing much flood damage in the Caribbean.Meanwhile,the bolide itself excavated 100 cubic kilometers of rock and debris from the site,which rose to an altitude of 100 kilometers.Most of it fell back immediately,but some of it remained as dust in the atmosphere
14、 for months.This material,along with the smoke from the fires,shrouded Earth,creating a form of nuclear winter.According to computerized climate models,global temperatures fell to near the freezing point,photosynthesis halted,and most plants on land and in the sea died.With the bottom of the food ch
15、ain destroyed,dinosaurs could not survive. paragraph 1 Dinosaurs rapidly became extinct about 65 million years ago as part of a mass extinction known as the K-T event,because it is associated with a geological signature known as the K-T boundary,usually a thin band of sedimentation found in various
16、parts of the world(K is the traditional abbreviation for the Cretaceous,derived from the German name Kreidezeit).Many explanations have been proposed for why dinosaurs became extinct.For example,some have blamed dinosaur extinction on the development of flowering plants,which were supposedly more di
17、fficult to digest and could have caused constipation or indigestionexcept that flowering plants first evolved in the Early Cretaceous,about 60 million years before the dinosaurs died out.In fact,several scientists have suggested that the duckbill dinosaurs and homed dinosaurs,with their complex batt
18、ery of grinding teeth,evolved to exploit this new resource of rapidly growing flowering plants Others have blamed extinction on competition from the mammals,which allegedly ate all the dinosaur eggsexcept that mammals and dinosaurs appeared at the same time in the Late Triassic,about 190 million yea
19、rs ago,and there is no reason to believe that mammals suddenly acquired a taste for dinosaur eggs after 120 million years of coexistence Some explanations(such as the one stating that dinosaurs all died of diseases)fail because there is no way to scientifically test them,and they cannot move beyond
20、the realm of speculation and guesswork. 1.In paragraph 1,why does the author include a discussion of when flowering plants evolved? 【事实信息题】 A.To help explain why some scientists believe that the development of flowering plants led to dinosaur extinction B.To cast doubt on the theory that the develop
21、ment of flowering plants caused dinosaurs to become extinct C.To suggest that dinosaurs were able to survive for as long as they did because of the availability of flowering plants D.To emphasize that duckbill dinosaurs and horned dinosaurs were the first dinosaurs to become extinct 答案:B 解析:根据 flowe
22、ring plants evolved 定位至 except that flowering plants first evolved in the Early Cretaceous,看其前面一句话 Many explanations have been proposed for why dinosaurs became extinct.For example,some have blamed dinosaur extinction on the development of flowering plants,作者提及开花植物的原因就是为了怀疑一些说开 花植物导致恐龙灭绝的理论,所以可知 B 选
23、项正确。 2.The word“allegedly”in the passage is closest in meaning to【词汇题】 A.inevitably B.gradually C.Supposedly D.Increasingly 答案:C 解析:allegedly,依其申述,据说,据称。 Inevitably,不可避免地。Gradually,渐渐地。Supposedly,按照推测。Increasingly,增 加地。所以 C 选项正确。 3.According to paragraph 1 the extinction of the dinosaurs is unlikely
24、 to have been the result of competition from mammals because【事实信息题】 A.mammals would not have been capable of eating dinosaur eggs B.mammals did not appear in any significant numbers until after the Late Triassic C.mammals and dinosaurs did not,in fact,compete for any of the same resources D.mammals
25、and dinosaurs lived together for roughly 120 million years before the extinction 答案:D 解析:根据 competition from mammals 定位至原文 and there is no reason to believe that mammals suddenly acquired a taste for dinosaur eggs after 120 million years of coexistence,可知哺乳动物之间的竞争并不会成为恐龙灭绝的原因是因为哺乳动物和恐龙一 起共存了一亿两千万年,所
26、以 D 选项正确。 paragraph 2 This focus on explaining dinosaur extinction misses an important point the extinction at the end of the Cretaceous was a global event that killed off organisms up and down the food chain.It wiped out many kinds of plankton in the ocean and many marine organisms that lived on th
27、e plankton at the base of the food chain.These included a variety of clams and snails,and especially the ammonites,a group of shelled squidlike creatures that dominated the Mesozoic seas and had survived many previous mass extinctions.The K-T event marked the end of the marine reptiles,such as the m
28、osasaurs and the plesiosaurs,which were the largest creatures that had ever lived in the seas and which ruled the seas long before whales evolved.On land,there was also a crisis among the land plants,in addition to the disappearance of dinosaurs.So any event that can explain the destruction of the b
29、ase of the food chain(plankton in the ocean,plants on land)can better explain what happened to organisms at the top of the food chain,such as the dinosaurs.By contrast,any explanation that focuses strictly on the dinosaurs completely misses the point The Cretaceous extinctions were a global phenomen
30、on,and dinosaurs were just a part of a bigger picture. 本文是托福 tpo42 阅读题目及答案解析:Explaining Dinosaur Extinction。 paragraph 3 According to one theory,the Age of Dinosaurs ended suddenly 65 million years ago when a giant rock from space plummeted to Earth.Estimated to be ten to fifteen kilometers in diame
31、ter,this bolide(either a comet or an asteroid)was traveling at cosmic speeds of 20-70 kilometers per second,or 45,000-156,000 miles per hour.Such a huge mass traveling at such tremendous speeds carries an enormous amount of energy.When the bolide struck this energy was released and generated a huge
32、shock wave that leveled everything for thousands of kilometers around the impact and caused most of the landscape to burst into flames.The bolide struck an area of the Yucatan Peninsula of Mexico known as Chicxulub,excavating a crater 15-20 kilometers deep and at least 170 kilometers in diameter.The
33、 impact displaced huge volumes of seawater,causing much flood damage in the Caribbean.Meanwhile,the bolide itself excavated 100 cubic kilometers of rock and debris from the site,which rose to an altitude of 100 kilometers.Most of it fell back immediately,but some of it remained as dust in the atmosp
34、here for months.This material,along with the smoke from the fires,shrouded Earth,creating a form of nuclear winter.According to computerized climate models,global temperatures fell to near the freezing point,photosynthesis halted,and most plants on land and in the sea died.With the bottom of the foo
35、d chain destroyed,dinosaurs could not survive. 4.According to paragraph 2,what is problematic about some scientistsfocus on dinosaur extinction?【事实信息题】 A.Dinosaurs became extinct so long ago that no theory about their disappearance can be proven scientifically. B.Dinosaurs were not the only organism
36、s that went extinct at the end of the Cretaceous period. C.More marine organisms went extinct during the Cretaceous than did dinosaur species. D.It is more important to understand how plankton and other marine organisms came to thrive during the Cretaceous period. 答案:B 解析:根据原文 This focus on explaini
37、ng dinosaur extinction misses an important point the extinction at the end of the Cretaceous was a global event that killed off organisms up and down the food chain.可知, 灭绝的生物并非只有恐龙, 还有很多食物链上 的生物体。所以 B 选项正确。 5.According to paragraph 2,each of the following became extinct during the K-T event EXCEPT 【
38、否定事实信息题】 A.early species of whales B.marine reptiles C.various species of clams D.many species of land plants 答案:A 解析 : 根据原文The K-T event marked the end of the marine reptiles,对应B选项。These included a variety of clams and snails,对应 C 选项。On land,there was also a crisis among the land plants,对应 D 选项。所以选
39、择 A 选项。 6.What makes the extinction of“the ammonites” especially significant?【事实信息 题】 A.They were among the largest creatures that ever lived. B.They existed at the lowest level of the food chain. C.They had been able to survive in the Mesozoic seas. D.They had survived many previous mass extinction
40、s. 答案:D 解析:根据 the ammonites 定位至原文 and especially the ammonites,a group of shelled squid like creatures that dominated the Mesozoic seas and had survived many previous mass extinctions.可知 D 选项正确。 7.The word“halted”in the passage is closest in meaning to【词汇题】 A.slowed B.stopped C.contracted D.declined
41、 答案:B 解析:halted,停止,休息。 Slowed,减慢。Stopped,停止。Contracted,感染,收缩,订约。Declined,减少。所以 B 选项正确。 8.The word“strictly“in the passage is closest in meaning to【词汇题】 A.exclusively B.mainly C.initially D.Wrongly 答案:A 解析:strictly,严格地。 Exclusively,唯一地,专有地。Mainly,主要地。Initially,最初。Wrongly,错误地。所 以 A 选项正确。 9.The word“cr
42、isis”in the passage is closest in meaning to【词汇题】 A.collapse B.disturbance C.critical situation D.loss 答案:C 解析:crisis,危机,决定性时刻。 Collapse,倒塌,衰竭。 Disturbance,干扰, 骚乱。 Critical situation,紧急情况。 Loss, 亏损,遗失。所以 C 选项正确。 10.How does paragraph 3 relate to paragraph 2?【组织结构题】 A.Paragraph 3 provides an alternat
43、ive explanation to the one provided in paragraph 2. B.Paragraph 3 provides an explanation that satisfies the conditions set forth in paragraph 2. C.Paragraph 3 provides the facts to support the theory presented in paragraph 2. D.Paragraph 3 presents a theory that calls into question the position des
44、cribed in paragraph 2. 答案:B 解析 : 根据原文 The Cretaceous extinctions were a global phenomenon 可知,第二段主 要讲白垩纪灭绝事件是一个全球现象,第三段继续解释另外一个理论,在六千五百万年前, 当太空里的一个巨大的石头垂直落向地球时,恐龙时代就突然结束了。继而以火流星坠落展 开详细解释。所以可知 B 选项正确。 paragraph 3 According to one theory,the Age of Dinosaurs ended suddenly 65 million years ago when a g
45、iant rock from space plummeted to Earth.Estimated to be ten to fifteen kilometers in diameter,this bolide(either a comet or an asteroid)was traveling at cosmic speeds of 20-70 kilometers per second,or 45,000-156,000 miles per hour.Such a huge mass traveling at such tremendous speeds carries an enorm
46、ous amount of energy.When the bolide struck this energy was released and generated a huge shock wave that leveled everything for thousands of kilometers around the impact and caused most of the landscape to burst into flames.The bolide struck an area of the Yucatan Peninsula of Mexico known as Chicx
47、ulub,excavating a crater 15-20 kilometers deep and at least 170 kilometers in diameter.The impact displaced huge volumes of seawater,causing much flood damage in the Caribbean.Meanwhile,the bolide itself excavated 100 cubic kilometers of rock and debris from the site,which rose to an altitude of 100
48、 kilometers.Most of it fell back immediately,but some of it remained as dust in the atmosphere for months.This material,along with the smoke from the fires,shrouded Earth,creating a form of nuclear winter.According to computerized climate models,global temperatures fell to near the freezing point,ph
49、otosynthesis halted,and most plants on land and in the sea died.With the bottom of the food chain destroyed,dinosaurs could not survive. 11.Paragraph 3 answers all of the following questions EXCEPT:【否定事实信息题】 A.Why did the bolide fall to Earth? B.How fast was the bolide traveling? C.How was the bolide capable of generating a shock wave? D.How did the bolide cause flood damage to the Caribbean? 答案:A 解析:原文 this bolide(either a comet or an asteroid)was traveling at cosmic speeds of 20-70 kilometers per second,or 45,000-156,000 miles per hour.对应 B 选 项。Such a huge mass traveling at such tremend
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