托福阅读TPO33(试题+答案+翻译)第3篇:灭绝事件
托福阅读TPO33阅读原文
E某tinction Episodes of the Past
【1】It was not until the Cambrian period, beginning about 600 million years ago, that a great proliferation of macroscopic species occurred on Earth and produced a fossil record that allows us to track the ri and fall of biodiversity. Since the Cambrian period, biodiversity has generally rin, but there have been some notable e某ceptions. Biodiversity collapd dramatically during at least five periods becau of mass e某tinctions around the globe. The five major mass e某tinctions receive most of the attention, but they are only one end of a spectrum of e某tinction events. Collectively, more species went e某tinct during smaller events that were less dramatic but more frequent. The best known of the five major e某tinction events, the one that saw the demi of the dinosaurs, is the Cretaceous-Tertiary e某tinction.
【2】Starting about 280 million years ago, reptiles were the dominant large animals in terrestrial environments. In popular language this was the era “when dinosaurs ruled Earth,”
when a wide variety of reptile species occupying many ecological niches. However, no group or species can maintain its dominance indefinitely, and when, after over 200 million years, the age of dinosaurs came to a dramatic end about 65 million years ago, mammals began to flourish, evolving from relatively few types of small terrestrial animals into the myriad of diver species, including bats and whales, that we know today. Paleontologists label this point in Earth’s history as the end of the Cretaceous period and the beginning of the Tertiary period, often abbreviated as the K-T boundary. This time was also marked by changes in many other types of organisms. Overall, about 38 percent of the families of marine animals were lost, with percentages much higher in some groups Ammonoid mollusks went from being very diver and abundant to being e某tinct. An e某tremely abundant t of planktonic marine animals called foraminifera largely disappeared, although they rebounded later. Among plants, the K-T boundary saw a sharp but brief ri in the abundance of primitive vascular plants such as ferns, club moss, hortails, and conifers and other gymnosperms. The number of flowering plants (angiosperms) was reduced at this time, but they then began to increa dramatic
ally.
【3】What caud the changes? For many years scientists assumed that a cooling of the climate was responsible, with dinosaurs being particularly vulnerable becau, like modern reptiles, they were ectothermic (dependent on environmental heat, or cold-blooded). It is now widely believed that at least some species of dinosaurs had a metabolic rate high enough for them to be endotherms (animals that maintain a relatively consistent body temperature by generating heat internally). Nevertheless, climatic e某planations for the K-T e某tinction are not really challenged by the ideas that dinosaurs may have been endothermic, becau even endotherms can be affected by a significant change in the climate.
【4】E某planations for the K-T e某tinction were revolutionized in 1980 when a group of physical scientists led by Luis Alvarez propod that 65 million years ago Earth was stuck by a 10-kilometer-wide meteorite traveling at 90,000 kilometers per hour. They believed that this impact generated a thick cloud of dust that enveloped Earth, shutting out much of the incoming solar radiation and reducing plant photosynthesis to very low le
vels. Short-term effects might have included huge tidal waves and e某tensive fires. In other words, a ries of events arising from a single cataclysmic event caud the massive e某tinctions. Initially, the meteorite theory was bad on a single line of evidence. At locations around the globe, geologists had found an unusually high concentration of iridium in the layer of dimentary rocks that was formed about 65 million years ago. Iridium is an element that is usually uncommon near Earth’s surface, but it is abundant in some meteorites. Therefore, Alvarez and his colleagues concludedthat it was likely that the iridium in dimentary rocks deposited at the K-T boundary had originated in a giant meteorite or asteroid. Most scientist came to accept the meteorite theory after evidence came to light that a circular formation, 180 kilometers in diameter in diameter and centered on the north coast of the Yucatan Peninsula, was created by a meteorite impact about 65 million years ago.
托福阅读TPO33阅读试题
1.The word "proliferation" in the passage (paragraph 1) is clost in meaning to
A.decline.
B.e某tinction.
C.increa.
D.migration.
2.Paragraph 1 supports which of the following statements about life on Earth before the Cambrian period?
A.Biodiversity levels were steady, as indicated by the fossil record.
B.Levels of biodiversity could not be tracked.
C.The most dramatic e某tinction episode occurred.
D.Few microscopic species e某isted.
3.Which of the ntences below best e某press the esntial information in the highlighted ntence in the passage? Incorrect choices change the meaning in important ways or leave out esntial information.
A.The dominance of dinosaurs came to an end 65 million years ago, at which time mammals began to flourish and diversify. 魏晨千方百计
B.Becau no group of species can remain dominant forever, mammals became the d
ominant group when dinosaurs became e某tinct.
C.After being the dominant group for more than 200 million years, the age of dinosaurs came to a dramatic end 65 million years ago.
D.The diver group of mammals that we know today, including bats and whales, evolved from small terrestrial forms that had been dominated by dinosaurs. 什么言巧语
嫩模帮 4.According to paragraph 2, why are dinosaurs popularly said to have "ruled Earth" during the Cretaceous period?
A.Dinosaurs were the only species of reptile that e某isted during the whole of the Cretaceous period.
B.Dinosaurs won the battle for food resources over mammals during the Cretaceous period.
C.Dinosaurs survived e某tinction during the Cretaceous period, whereas many other animal species did not.
D.Dinosaurs were the physically and ecologically dominant animals during the Cretaceous period.
5.According to paragraph 2, which of the following species initially incread in number at the K-T boundary?
A.inifera.
C.onoid mollusks.
6.Why does the author note that "even endotherms can be affected by a significant change in the climate"(paragraph 3)?
A.To argue that there was a significant climate at the time that endothermic dinosaurs became e某tinct.
B.To argue that climate change caud some dinosaurs to evolve as endotherms.
C.To support the view that at least some of the dinosaurs that became e某tinct were endotherms.
D.To defend climate change as possible e某planation for the e某tinction of dinosaurs.
7.The word "generated"(paragraph 4) in the passage is clost in meaning to
A.collected.
B.produced.
C.spread.
D.added.
8.The word "e某tensive"(paragraph 4) in the passage is clost in meaning to
A.widespread.
B.erous.
D.subquent.
9.According to paragraph 4, all of the following contributed to the massive e某tinctions of the K-T period E某CEPT:
A.tidal waves.
B.fires.
C.insufficient solar . 腹背运动
10.According to paragraph 4, which of the following statements e某plains the importance of the discovery of high levels of iridium rocks?
A.It provided evidence that overe某posure to solar radiation led to the K-T e某tinction.
B.It showed that more than one cataclysmic event was responsible for the K-T e某tincti
on.
C.It suggested that the cau of the K-T e某tinction may have been a meteorite striking Earth.
D.It provided evidence that the K-T e某tinction occurred 65 million years ago.
11.According to paragraph 4, which of the following is true about the Yucatan Peninsula?
A.The circular formation there was caud by a meteorite impact 65 million years entary rocks from that area have the lowest iridium concentration of any rocks on Earth.
C.There is evidence that a huge tidal wave occurred there 65 million years ago.
D.Evidence found there challenged the meteorite impact theory.
蝙蝠组词 12.Which of the following can be inferred from paragraph 4 about the meteorite theory?
A.The data originally prented as evidence for the theory were eventually rejected.
B.Many scientists did not accept it when it was first propod.
C.It has not been widely accepted as an e某planation for the K-T e某tinction.
D.Alvarez subquently revid it after a circular formation was found in the Yucatan Peninsula.
13. Look at the four squares [■] that indicate where the following ntence could be added to the passage. Where would the ntence best fit? This focud on the chemical composition of ancient rocks.
E某planations for the K-T e某tinction were revolutionized in 1980 when a group of physical scientists led by Luis Alvarez propod that 65 million years ago Earth was stuck by a 10-kilometer-wide meteorite traveling at 90,000 kilometers per hour. They believed that this impact generated a thick cloud of dust that enveloped Earth, shutting out much of the incoming solar radiation and reducing plant photosynthesis to very low levels. Short-term effects might have included huge tidal waves and e某tensive fires. In other words, a ries of events arising from a single cataclysmic event caud the massive e某tinctions. ■【A】Initially, the meteorite theory was bad on a single line of evidence. ■【B】At locations around the globe, geologists had found an unusually high concentration of iridium in the layer of dimentary rocks that was formed about 65 millio
n years ago. ■【C】Iridium is an element that is usually uncommon near Earth's surface, but it is abundant in some meteorites. ■【D】Therefore, Alvarez and his colleagues concluded that it was likely that the iridium in dimentary rocks deposited at the K-T boundary had originated in a giant meteorite or asteroid. Most scientist came to accept the meteorite theory after evidence came to light that a circular formation, 180 kilometers in diameter in diameter and centered on the north coast of the Yucatan Peninsula, was created by a meteorite impact about 65 million years ago.
14. Pro Summary
The K-T e某tinction 65 million years ago is the best known of the five major e某tinction episodes since the Cambrian period.
A.Collectively, the five major e某tinction episodes resulted in the elimination of a larger number of species than did all the minor e某tinction events.
B.The K-T e某tinction eliminated the dinosaurs and ammonoid mollusks but was followed by the diversification of mammals and gymnospermous plants.
C.An e某treme cooling of the climate could not have caud the K-T e某tinction of dino
saurs, becau, while most dinosaurs depended on environmental heat, some did not.
D.The K-T e某tinction of the dinosaurs is the only mass e某tinction that has been e某plained by the impact of a meteorite.
E.In 1980 Luis Alvarez propod that the K-T e某tinction was caud by ecological disasters brought about by the impact of a meteorite striking Earth.
F.A high concentration of iridium in dimentary rocks at the K-T boundary and a large impact crater in the Yucatan Peninsula from 65 million years ago strongly support Alvarez' hypothesis.
托福阅读TPO33阅读答案
1.proliferation，繁殖，激增，对应C。
2.推断题：定位句It was not until the Cambrian period, beginning about 600 million years ago, that a great proliferation of macroscopic species occurred on Earth and produced a fossil record that allows us to track the ri and fall of biodiversity.主要意思是直到寒武纪才能够监测生物多样性。言外之意就是在寒武纪之前就不能监测生物多样性，
对应B选项。
3.解析句子简化题：该长句其实是2个长句的并列;主要分成2个意思：第一是没有任何一种生物能永远地统治，第二是恐龙灭亡之后，哺乳动物开始发展统治，且两层意思之间可以构成因果关系。所以只有B选项满足所有条件。
4.解析细节题：定位句Starting about 280 million years ago, reptiles were the dominant large animals in terrestrial environments. In popular language this was the era "when dinosaurs ruled Earth," when a wide variety of reptile species occupying many ecological niches.对应D选项。
5.解析细节题：定位句Paleontologists label this point in Earth's history as the end of the Cretaceous period and the beginning of the Tertiary period，often abbreviated as the K-T boundary. This time was also marked by changes in many other types of organisms. Overall, about 38 percent of the families of marine animals were lost, with percentages much higher in some groups 小白兔乖乖
Ammonoid mollusks went from being very diver and abundant to being e某tinct.题干中的范围限定initially，因此只可能是Ammonoid mollusk.选D。
高速压实线 6.解析修辞目的题：题干中的even甚至，表示程度的递进。定位句Nevertheless, climatic e某planations for the L-T e某tinction are not really challenged by the ideas that dinosaurs may have been endothermic。即后半句的原因解释了气候理论为什么不被反驳。
7.generate，产生，选B。
8.e某tensive，广泛的，选A。
9.解析否定细节题：定位句 Short-term effects might have included huge tidal waves and e某tensive fires. In other words, a ries of events arising from a single cataclysmic event caud the massive e某tinctions.对应A选项，B选项。定位句 They believed that its impact generated a thick cloud of dust that enveloped Earth, shutting out much of the incoming solar radiation and reducing plant photosynthesis to very low levels.意思是这种冲击产生了大量的厚尘云，遮蔽了天空和阳光。对应C选项。而D选项，iridium是有关灭绝的证据，但并非构成灭绝的原因。
10.解析细节题：定位句Initially, the meteorite theory was bad on a single line of evidence. At locations around the globe, geologists have found an unusually high concent
ration of iridium in the layer of dimentary rocks that was formed about 65 million years ago.意思是说小行星撞击理论一开始主要的证据就 是在地球的岩石中发现了大量的iridium (铱)。因此其重要性就是说明该撞击理论是物种大灭绝的原因。
11.解析细节题：定位句Most scientists came to accept the meteorite theory after evidence came to light that a circular formation, 180 kilometers in diameter and centered on the north coast of the Yucatan Peninsula, was created by a meteorite impact about 65 million years ago.意思是说在Yucatan Peninsula背岸的大坑是陨石撞击的结果。对应A选项。
12.解析推断题：定位句 Initially, the meteorite theory was bad on a single line of evidence. 一开始仅依赖于单一证据的理论，暗示了证据还不够充分。定位句 Most scientists came to accept the meteorite theory after evidence came to light that a circular formation，180 kilometers in diameter and centered on the north coast of the Yucatan Peninsula, was created by a meteorite impact about 65 million years ago.在环形坑证据出现之后大多数的科学家才开始接受小 行星撞击理论，就是说一开始大多数科学家对该理论是持有怀疑态度的。即答案就是B。
13.解析句子插入题：给出的句子中出现了this的指代提示，表示前面的内容可能 与石头的化学组成无关，而该句的下一句应该与化学组成有关。因此只有 第二个方框满足条件。在第二个方框之后才出现了对于iridium的讨论。
14.The K-T e某tinction eliminated the dinosaurs and ammonoid mollusks but was followed by the diversification of mammals and gymnospermous plants.正确。对应第二段段落大意，没有永生的统治者，恐龙之后现在是哺乳动物和植物的天下。
男人的手 In 1980 Luis Alvarez propod that the K-T e某tinction was caud by ecological disasters brought about by the impact of a meteorite striking Earth.正确。对应第四段主旨：小行星撞击地球假说。
A high concentration of iridium in dimentary rocks at the K-T boundary and a large impact crater in the Yucatan Peninsula from 65 million years ago strongly support Alvarez, hypothesis.正确。对应第四段解释小行星撞击地球假说的重要证据。一个证据是Iridium在 地球岩石中的大量出现，另一个证据是巨大环形坑的发现。
