1、【光年教育留學最后一站】 課程咨詢zouzhongjie526TOEFL【光年教育】光年 TOEFL 系列資料回顧練習+講解20190713 閱讀TOEFL1【光年教育留學最后一站】 課程咨詢zouzhongjie526【光年教育】“光年教育”位于中國教育科研第三城江蘇南京，由留學培訓業內名師前南京環球院院長/南京培訓行業“十大名師”之一牽頭創建，專注于/三大項目，截止 2018 年 12 月，已經有超過 1000 名線下集訓課程學員，超過 20000 名線上課程學員取得理想成績，順利赴美繼續深造。光年教育課程深受各地考生追捧，風靡全網，以至于淘寶各大賣家爭相銷售相關系列課程，更多考生接觸到更

2、優質的正版教學素材和教學，光年教育從 2014 年開始推行“線上線下”雙線并行授課模式，致力于光年教育，入學項目提分培訓。留學最后一站。TOEFL 備考信息請關注“光年 TOEFL”2【光年教育留學最后一站】 課程咨詢zouzhongjie526閱讀3【光年教育留學最后一站】 課程咨詢zouzhongjie526Why did nonavian dinosaurs become extinct?Data from diverse sources, indicates that the Late Cretaceous climate was milder than todays because

3、of shallow seas covering the continents. At the end of the Cretaceous, the geological record shows that these seaways retreated from the continents back into the major ocean basins. No one knows why. Over a period of about 100,000 years, while the seas pulled back, climates around the world became d

4、ramatically more extreme: warmer days, cooler nights: hotter summers, colder winters. Perhaps Nonavian dinosaurs(that is , all the dinosaurs except those belonging to the Ave, or bird family)could not tolerate these extreme temperature changes and become extinct.If true though, why did cold-blooded

5、animals, such as snakes, lizards, turtles, and crocodiles survive the freezing winters and torrid summers? These animals are at the mercy of the climate to maintain a livable body temperature. Its hard to understand why they would not be affected, whereas Nonavian dinosaurs were left too crippled to

6、 cope, especially if some dinosaurs were warm-blooded. Critics also point out that the shallow seaways had retreated from and advanced not the continents numerous times during the Mesozoic, so why did the nonavian dinosaurs survive the climatic changes associated with the earlier fluctuations but no

7、t with this one? Although initially appealing, thehypothesis of a simple climatic change related to sea levels is insufficient to explain all the data.Volcanism, has also been implicated in dinosaur extinction. The end of the Cretaceous coincided with a great increase in volcanic activity throughout

8、 the world. Lava flooded areas of India, and explosive eruptions in the South Atlantic and the midwestern United States hurled ash over much of the globe. These eruptions could have spewed great quantities of poisonous gases into the atmosphere causing acid rain and more-acidic waters in the surface

9、 layers of the ocean. Over the short term, a cooling would result from the airborne volcanic ash, which would cut off sunlight. Over a longer term, warming could have resulted from the greenhouse effect. Climatic changes from increased volcanism may have caused the extinction of many nonavian dinosa

10、urs, but they do not satisfactorily explain the selective patterns of extinction inthe fossil record.Dissatisfaction with conventional explanations for nonavian dinosaur extinctions eventually led to a key observation that, in turn, has fueled a decade of vigorous and often vitriolic debate. Many pl

11、ants and animals that become extinct at the end of the Mesozoic disappear abruptly as one moves from older layers of rock documenting the end of the Cretaceous up into younger rocks representing the beginning of the Cenozoic. Between the last layer representing the end of the Cretaceous and the firs

12、t layer representing the start of the Cainozoic, there is often a thin bed of clay. Scientists felt that they could get an idea of how long it took to deposit this 1 centimeter of clay by looking at theconcentration of the element iridium in it.Iridium is no longer common at Earths surface. Because

13、it usually exists in a mlic state, it was preferentiallyincorporated into Earths core as the planet cooled and consolidated. Iridium is found in high concentrations in somemeteorites in which the solar systems original chemical composition is p. Even today, microscopic meteoritescontinually bombard

14、Earth, falling on both land and sea. By measuring how many of these meteorites fall to Earth over a given period of time, scientists can estimate how long it might have taken to deposit the observed amount of iridium in the boundary clay. These calculations suggest that a period of about 1 million y

15、ears would have venn required. On the basis of other evidence related to Earths magnetic field at the time of the extinction, however, it was believed thatnonavian dinosaurs and other animals had to have gone extinct within a period of half a million years. If so, the4【光年教育留學最后一站】 課程咨詢zouzhongjie526

16、deposition of the boundary clay could not have lasted 1 million years, and the unusually high concentration of iridiumseemed to require a special explanation.Consequently, scientists hypothesized that a single large asteroid, about 10 to 15 kilometers across, collided with Earth, and the resulting f

17、allout created the boundary clay. Their calculations show that the impact kicked up a dust cloud that cut off slight for several months, inciting photosynthesis in plants; decreased surface temperatures on continents to below freezing; caused extreme episodes of acid rain; and significantly raised l

18、ong-term global temperatures through the greenhouse effect, This disruption of the food chain an climate would have eradicated the nonavian dinosaurs andother organisms in less than 50 years.Paragraph 1Data from diverse sources, indicates that the Late Cretaceous climate was milder than todays becau

19、se of shallow seas covering the continents. At the end of the Cretaceous, the geological record shows that these seaways retreated from the continents back into the major ocean basins. No one knows why. Over a period of about 100,000 years, while the seas pulled back, climates around the world becam

20、e dramatically more extreme: warmer days, cooler nights: hotter summers, colder winters. Perhaps Nonavian dinosaurs(that is , all the dinosaurs except those belonging to the Ave, or bird family) could not tolerate these extreme temperature changes and become extinct.1. According to paragraph 1, the

21、presence of large amounts of water on continents during the Late Cretaceous causedclimate conditions that were more extreme than todays climate reduction on the size of the major ocean basins around the worldtemperatures that probably made it more difficult for some dinosaurs to survivecooler summer

22、 temperatures and warmer winter temperatesParagraph 2If true though, why did cold-blooded animals, such as snakes, lizards, turtles, and crocodiles survive the freezing winters and torrid summers? These animals are at the mercy of the climate to maintain a livable body temperature. Its hard to under

23、stand why they would not be affected, whereas Nonavian dinosaurs were left too crippled to cope, especially if some dinosaurs were warm-blooded. Critics also point out that the shallow seaways had retreated from and advanced not the continents numerous times during the Mesozoic, so why did the nonav

24、ian dinosaurs survive the climatic changes associated with the earlier fluctuations but not with this one? Although initially appealing, thehypothesis of a simple climatic change related to sea levels is insufficient to explain all the data.2. Which of the sentences below best expresses the essentia

25、l information in the highlighted sentence in the passage?Incorrect change the meaning in important ways or leave out essential information.Critics believe that the shallow seaways had advanced on and then retreated from the continents significantly earlier, during the MesozoicAnother problem with th

26、is theory is that the nonavian dinosaurs survived many changes in levels of the continental seas during MesozoicCritics have not been able to explain why the nonavian dinosaurs survived the climatic changes that happened when seas fell during the MesozoicThe continental sea rose and fell many times

27、during the Mesozoic as well, but the resulting climatic changes werenot as severe5【光年教育留學最后一站】 課程咨詢zouzhongjie5263. In paragraph 2, why does the author bring up the fact that snake, lizards,turtles, and crocodiles all survived extinctionwhen nonavian dinosaurs did not?To provide evidence that nonavi

28、an dinosaurs were particular sensitive to climate change To argue that at least some dinosaurs were warm-bloodedTo point out that snakes, lizards, turtles, and crocodiles were well adapted to the new climate conditionsTo challenge the idea that the extinction of nonavian dinosaurs was cased simply b

29、y climate changeParagraph 3Volcanism, has also been implicated in dinosaur extinction. The end of the Cretaceous coincided with a great increase in volcanic activity throughout the world. Lava flooded areas of India, and explosive eruptions in the South Atlantic and the midwestern United States hurl

30、ed ash over much of the globe. These eruptions could have spewed great quantities of poisonous gases into the atmosphere causing acid rain and more-acidic waters in the surface layers of the ocean. Over the short term, a cooling would result from the airborne volcanic ash, which would cut off sunlig

31、ht. Over a longer term, warming could have resulted from the greenhouse effect. Climatic changes from increased volcanism may have caused the extinction of many nonavian dinosaurs, but they do not satisfactorily explain the selective patterns of extinction inthe fossil record.4. According to paragra

32、ph 3, the increase in volcanism does NOT explain which of the following?which species become extinct and which survivedwhy climate mate seems to have become temporally cooler Changes in water acidity in the surface layers of the ocean The presence of poisonous gases in the atmosphereParagraph 4Dissa

33、tisfaction with conventional explanations for nonavian dinosaur extinctions eventually led to a key observation that, in turn, has fueled a decade of vigorous and often vitriolic debate. Many plants and animals that become extinct at the end of the Mesozoic disappear abruptly as one moves from older

34、 layers of rock documenting the end of the Cretaceous up into younger rocks representing the beginning of the Cenozoic. Between the last layer representing the end of the Cretaceous and the first layer representing the start of the Cainozoic, there is often a thin bed of clay. Scientists felt that t

35、hey could get an idea of how long it took to deposit this 1 centimeter of clay by looking at theconcentration of the element iridium in it.5.The word “vigorous” in the passage is closet in meaning toenergetic scientific continuousproductive6.The word “abruptly” in the passage is closet in meaning to

36、suddenly and unexpectedly initiallyeventuallywith explanation6【光年教育留學最后一站】 課程咨詢zouzhongjie5267. Paragraph 4 suggests that scientists were initially interested in the layer of clay because they wanted to know whichof the following about the Earths history?what the climate was like at the start of the

37、 Cenozoic periodthe levels of iridium in rocks from the Cenozoic compared with levels in rocks from the Cretaceous how this bed of clay formed such an extremely thin layerwhether there was a connection between the clay and how quickly extinction occurredParagraph 5Iridium is no longer common at Eart

38、hs surface. Because it usually exists in a mlic state, it was preferentiallyincorporated into Earths core as the planet cooled and consolidated. Iridium is found in high concentrations in somemeteorites in which the solar systems original chemical composition is p. Even today, microscopic meteorites

39、continually bombard Earth, falling on both land and sea. By measuring how many of these meteorites fall to Earth over a given period of time, scientists can estimate how long it might have taken to deposit the observed amount of iridium in the boundary clay. These calculations suggest that a period

40、of about 1 million years would have venn required. On the basis of other evidence related to Earths magnetic field at the time of the extinction, however, it was believed that nonavian dinosaurs and other animals had to have gone extinct within a period of half a million years. If so, the deposition

41、 of the boundary clay could not have lasted 1 million years, and the unusually high concentration of iridiumseemed to require a special explanation.8. The word “continually” in the passage is closet in meaning tooccasionally obviously regularlygenerally9. Which of the following can be inferred form

42、paragraph 5 about iridium?It was present at the time the solar system originally formedThere is very little iridium found in Earth s coreIridium on meteorites is rarely in its mlic stateAt hight levels iridium toxic enough to have caused mass extinctions10. According to paragraph 5, as a result of d

43、etermining how long it took to despot the iridium-rich boundary clay,scientists realized thatmeteorites had stopped falling to Earth while the boundary clay was being deposited the thin bed of boundary clay was formed over a period of about one million years the thin bed of boundary clay layer was o

44、lder than they previously thoughtthe iridium in the boundary clay could not have been deposited through the usual processParagraph 6Consequently, scientists hypothesized that a single large asteroid, about 10 to 15 kilometers across, collided with Earth, and the resulting fallout created the boundar

45、y clay. Their calculations show that the impact kicked up a dust cloud that cut off slight for several months, inciting photosynthesis in plants; decreased surface temperatures on continents to below freezing; caused extreme episodes of acid rain; and significantly raised long-term global temperatur

46、es through7【光年教育留學最后一站】 課程咨詢zouzhongjie526the greenhouse effect, This disruption of the food chain an climate would have eradicated the nonavian dinosaurs andother organisms in less than 50 years.11. The word “eradicated” in the passage is closet in meaning toreached starved affectedeliminated12. Ac

47、cording to paragraph 6, the dust produced by the large asteroid collided with Earth led to all of the followingexcepta short-term drop in temperatures on land loss sunlight for several monthstemperately freezing of much the worlds oceanswarmer climate over the long termParagraph 1Data from diverse s

48、ources, indicates that the Late Cretaceous climate was milder than todays because of shallow seas covering the continents. At the end of the Cretaceous, the geological record shows that these seaways retreated from the continents back into the major ocean basins. No one knows why. Over a period of a

49、bout 100,000 years, while the seas pulled back, climates around the world became dramatically more extreme: warmer days, cooler nights: hotter summers, colder winters. Perhaps Nonavian dinosaurs (that is , all the dinosaurs except those belonging to the Ave, orbird family) could not tolerate these e

50、xtreme temperature changes and become extinct.13. Look at the four squaresthat indicate where the following sentence could be added to the passage.These large bodies of water kept the temperature of the nearby air bodies relatively constant from day to night, summer to winter.Where would the sentenc

51、e best fit? Click on a square to add the sentence to the passage.8【光年教育留學最后一站】 課程咨詢zouzhongjie52614. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the pass

52、age. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.The nonavian dinosaurs became extinct at the end of the Cretaceous period, and scientists have proposed severaltheories

53、 to explain why.Drag your choices to the spaces where they belong. To review the passage, click on View Text.Answer ChoicesIncrease volcanic activity led to acid rain, a short-term cooling of the atmosphere, and other harmful effects, but it does not explain the selective patterns of extinctionThe c

54、lay at Cretaceous - Cenozoic boundary is unusually rich in iridium, which suggests that the extinctions were caused by Earths collision with large asteroidLoss of continental seas made the climate more extreme, but some cold-blooded animals survived the change and the seas had retreated before witho

55、ut massive extinctions.There is evidence that calls into question the hypothesis that the seas retreated from the continents at the end of the Cretaceous periodIridium poisoning may have inhibited photosynthesis in plants, leading to a disruption of the food chain, but a disruption does not explain

56、the loss of all nonavian dinosaursEvidence of volcanic activity, during the Cretaceous period supports the huge and widespread volcanic eruptionstriggered the mass extinction.9【光年教育留學最后一站】 課程咨詢zouzhongjie526光年教育TOEFL 課程總體TOEFL 備考信息關注“光年 TOEFL”201910【光年教育】TOERE/GMAT留學最后一站課程咨詢zouzhongjie5261.光年教育“ 光年教育”位于中國教育科研第三城江蘇南京，由院院長/南京培訓行業“ 十大名師”之一留學培訓業內名師前南京牽頭創建，專注于TOEFL /GRE /GMAT 三大項目，截止 2018 年 12 月，已經有超過 1000 名線下集訓課程學員，超過 20000 名線上課程學員取得理想成績，順利赴美繼續深造。光年教育課程深受各地考生追捧，風靡，考生接觸到更優質的正版教學素材和教學， 光年教育從 2014 年開始推行“ 線上+線下”雙線并行授課模式，