Dinosaurs rapidly becameextinctabout 65 million years ago as part of amassextinctionknown as the K-T event, because it is associated with a geological signature known as the K-Tboundary, usually a thinbandofsedimentationfound in various parts of the world (K is thetraditionalabbreviation for theCretaceous, derived from the German name Kreidezeit). Many explanations have been proposed for why dinosaurs becameextinct. For example, some have blameddinosaurextinctionon thedevelopmentof flowering plants, which weresupposedlymore difficult todigestand could have caused constipation orindigestion- except that flowering plants first evolved in the EarlyCretaceous, about 60 million years before the dinosaurs died out. In fact, several scientists have suggested that the duckbill dinosaurs and horned dinosaurs, with theircomplexbatteryof grinding teeth, evolved toexploitthis newresourceof rapidly growing flowering plants. Others have blamedextinctionon competition from the mammals, which allegedly ate all thedinosaureggs—except that mammals and dinosaurs appeared at the same time in the Late Triassic, about 190 million years ago, and there is noreasonto believe that mammals suddenly acquired atastefordinosaureggs 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 therealmof speculation and guesswork.

Thisfocuson explainingdinosaurextinctionmisses an important point: theextinctionat the end of theCretaceouswas a global event that killed off organisms up and down the foodchain. It wiped out many kinds ofplanktonin the ocean and manymarineorganisms that lived on theplanktonat the base of the foodchain. These included avarietyof clams and snails, and especially the ammonites, a group of shelled squidlike creatures that dominated theMesozoicseas and had survived manypreviousmassextinctions. The K-T event marked the end of themarinereptiles, 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, inadditionto the disappearance of dinosaurs. So any event that can explain thedestructionof the base of the foodchain(planktonin the ocean, plants on land) can better explain what happened to organisms at the top of the foodchain, such as the dinosaurs. Bycontrast, any explanation that focuses strictly on the dinosaurs completely misses the point. TheCretaceousextinctions were a globalphenomenon, and dinosaurs were just a part of a bigger picture.

According to onetheory, the Age of Dinosaurs ended suddenly 65 million years ago when agiantrock fromspaceplummeted to Earth. Estimated to be ten to fifteen kilometers indiameter, this bolide (either acometor anasteroid) was traveling atcosmicspeeds of 20-70 kilometers per second, or 45,000-156,000 miles per hour. Such a hugemasstraveling at suchtremendousspeeds carries anenormousamountof energy. When the bolide struck this energy was released and generated a huge shock wave that leveled everything for thousands of kilometers around theimpactand caused most of thelandscapeto burst into flames. The bolide struck an area of the Yucatan Peninsula of Mexico known as Chicxulub, excavating acrater15-20 kilometers deep and atleast170 kilometers indiameter. Theimpactdisplaced huge volumes of seawater, causing much flood damage in the Caribbean. Meanwhile, the bolide itself excavated 100 cubic kilometers of rock anddebrisfrom the site, which rose to analtitudeof 100 kilometers. Most of it fell back immediately, but some of it remained as dust in theatmospherefor months. Thismaterial,alongwith the smoke from the fires, shrouded Earth, creating a form of nuclear winter. According to computerizedclimatemodels, global temperatures fell to near the freezing point,photosynthesishalted, and most plants on land and in the sea died. With the bottom of the foodchaindestroyed, dinosaurs could notsurvive.

Questions:
question_stem: In paragraph 1, why does the author include a discussion of when flowering plants evolved?
choices: tag: A
text: To help explain why some scientists believe that the development of flowering plants led to dinosaur extinction

tag: B
text: To cast doubt on the theory that the development of flowering plants caused dinosaurs to become extinct

tag: C
text: To suggest that dinosaurs were able to survive for as long as they did because of the availability of flowering plants

tag: D
text: To emphasize that duckbill dinosaurs and horned dinosaurs were the first dinosaurs to become extinct
answer_key: B
explanation: 【题目翻译】在第1段中，作者为什么要讨论开花植物何时进化？
A：为了解释为什么一些科学家认为开花植物的发展导致恐龙灭绝

B：对开花植物的发展导致恐龙灭绝的理论提出质疑

C：这说明恐龙之所以能活这么长时间，是因为有开花植物。

D：强调鸭嘴龙和角恐龙是第一批灭绝的恐龙。

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】：根据关键词 flowering plants evolved,定位到 Passage1 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.意思是“关于恐龙为何灭绝，人们提出了许多解释。例如，一些人将恐龙灭绝归咎于开花植物的发展”。

【逻辑分析】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。

【选项分析】
A.不是为了解释，而是为了提出疑问。故错误。
B.符合文意，正确。
C.作者在质疑这一观点，所以不是说明，故错误。
D.不是强调作用，故错误。

question_stem: The word “allegedly” in the passage is closest in meaning to
choices: tag: A
text: inevitably

tag: B
text: gradually

tag: C
text: supposedly

tag: D
text: increasingly
answer_key: C
explanation: 【题目翻译】文章中的“allegedly”一词最接近于下列哪个选项？
A：不可避免地

B：逐渐地

C：据说

D：越来越多地

【判定题型】：题目要求选出与高亮单词意思最接近的选项，故判断本题为词汇题。

【关键词定位】：根据关键词“allegedly”,定位到原句“Others have blamed extinction on competition from the mammals, which allegedly ate all the dinosaur egg……”。

【词汇解析】：词汇“allegedly”的意思是“依其申述，据说，据称”,带入到原句中，原句的意思是“另一些人则将灭绝归咎于哺乳动物的竞争，据说它们吃掉了所有恐龙蛋……”。

【选项分析】
A：不可避免地。不符，错误
B：逐渐地。不符，错误
C：据说。符合，正确
D：越来越多地。不符，错误

question_stem: According to paragraph 1, the extinction of the dinosaurs is unlikely to have been the result of competition from mammals because
choices: tag: A
text: mammals would not have been capable of eating dinosaur eggs

tag: B
text: mammals did not appear in any significant numbers until after the Late Triassic

tag: C
text: mammals and dinosaurs did not, in fact, compete for any of the same resources

tag: D
text: mammals and dinosaurs lived together for roughly 120 million years before the extinction
answer_key: D
explanation: 【题目翻译】根据第1段，恐龙的灭绝不太可能是哺乳动物竞争的结果，因为
A：哺乳动物不可能吃恐龙蛋。

B：直到晚三叠世之后，哺乳动物才大规模出现。

C：事实上，哺乳动物和恐龙没有争夺任何相同的资源。

D：哺乳动物和恐龙在灭绝前生活在一起大约1.2亿年

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】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，意思是“没有理由相信哺乳动物在经历了1.2亿年的共存之后，会突然尝到恐龙蛋的味道
【逻辑分析】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。

【选项分析】
A.文章中没有说哺乳动物不可能吃恐龙蛋，它们还是会吃的。故错误。
B.文章：哺乳动物和恐龙都生活在在约1.9亿万年前的晚三叠世。故错误。
C.未提及“争夺相同资源”，故错误。
D.符合原文意思，正确。

question_stem: According to paragraph 2, what is problematic about some scientists' focus on dinosaur extinction?
choices: tag: A
text: Dinosaurs became extinct so long ago that no theory about their disappearance can be proven scientifically.

tag: B
text: Dinosaurs were not the only organisms that went extinct at the end of the Cretaceous period.

tag: C
text: More marine organisms went extinct during the Cretaceous than did dinosaur species.

tag: D
text: It is more important to understand how plankton and other marine organisms came to thrive during the Cretaceous period.
answer_key: B
explanation: 【题目翻译】根据第2段，一些科学家关注恐龙灭绝有什么问题？
A：恐龙在很久以前就灭绝了，没有一个关于它们消失的理论可以被科学地证明。

B：恐龙并不是白垩纪末期唯一灭绝的生物。

C：在白垩纪灭绝的海洋生物比恐龙种类多。

D：更重要的是要了解浮游生物和其他海洋生物在白垩纪是如何繁衍的。

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】：根据关键词“dinosaur extinction”,定位到 Passage2，原句为“his 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.”，意思是“他对解释恐龙灭绝的关注忽略了一个重要的点：白垩纪末期的灭绝是一个全球性的事件，这次事件杀死的生物来自整个食物链”。

【逻辑分析】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。

【选项分析】
A.不符合文意，错误。
B.符合文意，正确。
C.文章未把海洋生物灭绝的种类和恐龙灭绝的种类相比较。故错误。
D.未提到繁衍，故错误。

question_stem: According to paragraph 2, each of the following became extinct during the K-T event EXCEPT
choices: tag: A
text: early species of whales

tag: B
text: marine reptiles

tag: C
text: various species of clams

tag: D
text: many species of land plants
answer_key: A
explanation: 【题目翻译】根据第2段，在 k-t 事件期间，以下每一个都灭绝了，除了下列哪个选项？
A：鲸鱼的早期物种

B：海洋爬行动物

C：各种蛤类

D：许多陆地植物

【判定题型】：根据题干中出现的大写“EXCEPT”/"NOT" 等其他明显表示否定的词，可以判定本题为否定事实信息题，需要找出与原文信息不符的那个答案。

【关键词定位】：根据题干关键词“K-T event”,可以将出题范围锁定在 Passage 2。

【选项分析】
A.未提及。错误。
B.根据原文 The K-T event marked the end of the marine reptiles，对应 B 选项。
C.hese included a variety of clams and snails,对应 C 选项。
D.On land, there was also a crisis among the land plants,对应 D 选项

question_stem: What makes the extinction of “the ammonites” especially significant?
choices: tag: A
text: They were among the largest creatures that ever lived.

tag: B
text: They existed at the lowest level of the food chain.

tag: C
text: They had been able to survive in the Mesozoic seas.

tag: D
text: They had survived many previous mass extinctions.
answer_key: D
explanation: 【题目翻译】什么使“菊石”的灭绝特别重要？
A：他们是有史以来最大的动物之一。

B：它们存在于食物链的最底层。

C：他们在中生代海洋中生存了下来。

D：它们在许多以前的大规模灭绝中幸存下来。

【判定题型】：题目问的是文章中的具体细节信息，故根据题目问法可以判断本题为事实信息题。

【关键词定位】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.意思是“尤其是菊石，一种类似鱿鱼的壳类生物，统治着中生代的海洋，并在许多以前的大规模灭绝中幸存下来。”。

【逻辑分析】：结合题目问法和出题句，进行逻辑分析。

【选项分析】
A.未说它是不是最大的动物。故错误。
B.未说它处于食物链的哪里，故错误。
C.文章：在以前的很多大规模灭绝中幸存了下来。选项描述有误，故错误。
D.符合文意，正确。

question_stem: The word “halted” in the passage is closest in meaning to
choices: tag: A
text: slowed

tag: B
text: stopped

tag: C
text: contracted

tag: D
text: declined
answer_key: B
explanation: 【题目翻译】段落中的“halted”一词最接近于下列哪个选项？
A：放慢

B：停止

C：感染，收缩，订约

D：减少

【判定题型】：题目要求选出与高亮单词意思最接近的选项，故判断本题为词汇题。

【关键词定位】：根据关键词“halted”,定位到原句“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. ”。

【词汇解析】：词汇“halted”的意思是“停止，休息”,带入到原句中，原句的意思是“根据计算机气候模型，全球温度降到接近冰点，光合作用停止，陆地和海洋中的大多数植物死亡”。

【选项分析】
A：放慢。不符，错误

B：停止。同义替换，正确

C：感染，收缩，订约。不符，错误

D：减少。不符，错误

question_stem: The word "strictly" in the passage is closest in meaning to
choices: tag: A
text: exclusively

tag: B
text: mainly

tag: C
text: initially

tag: D
text: wrongly
answer_key: A
explanation: 【题目翻译】段落中的“strictly”一词最接近于下列哪个选项？
A：唯一地，专有地
B：主要地

C：最初地

D：错误地

【判定题型】：题目要求选出与高亮单词意思最接近的选项，故判断本题为词汇题。

【关键词定位】：根据关键词“strictly”,定位到原句“By contrast, any explanation that focuses strictly on the dinosaurs completely misses the point. ”。

【词汇解析】：词汇“strictly”的意思是“ 严格地”,带入到原句中，原句的意思是“相比之下，那些只关注恐龙本身的解释就没有解释到点子上。”。

【选项分析】
A：唯一地，专有地。同义替换，正确
B：主要地。不符，错误
C：最初地。不符，错误
D：错误地。不符，错误

question_stem: The word “crisis” in the passage is closest in meaning to
choices: tag: A
text: collapse

tag: B
text: disturbance

tag: C
text: critical situation

tag: D
text: loss
answer_key: C
explanation: 【题目翻译】段落中的“crisis”一词最接近于下列哪个选项？
A：倒塌，衰竭
B：干扰，骚乱
C：紧急情况
D：亏损，遗失

【判定题型】：题目要求选出与高亮单词意思最接近的选项，故判断本题为词汇题。

【关键词定位】：根据关键词“crisis”,定位到原句“On land, there was also a crisis among the land plants, in addition to the disappearance of dinosaurs.”。

【词汇解析】：词汇“crisis”的意思是“危机，决定性时刻”,带入到原句中，原句的意思是“在陆地上，除了恐龙的消失，陆地植物也出现了危机”。

【选项分析】
A：倒塌，衰竭。不符，错误
B：干扰，骚乱。不符，错误
C：紧急情况。同义替换，正确
D：亏损，遗失。不符，错误

question_stem: How does paragraph 3 relate to paragraph 2?
choices: tag: A
text: Paragraph 3 provides an alternative explanation to the one provided in paragraph 2.

tag: B
text: Paragraph 3 provides an explanation that satisfies the conditions set forth in paragraph 2.

tag: C
text: Paragraph 3 provides the facts to support the theory presented in paragraph 2.

tag: D
text: Paragraph 3 presents a theory that calls into question the position described in paragraph 2.
answer_key: B
explanation: 【题目翻译】第3段与第2段有何关系？
A：第3款提供了对第2款规定的另一种解释。

B：第3段提供了满足第2段所述条件的解释。

C：第3段提供了支持第2段所述理论的事实。

D：第3段提出了一个理论，该理论对第2段所述的立场提出了质疑。

【判定题型】：根据题目问法，题目询问 xxx 组成或构成方式/段落与段落的关系/某一段在全文中所起的作用，故判断本题为组织结构题。

【内容分析】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。

【选项分析】
A.没有另一种解释，故错误。
B.符合文意，正确
C.是满足第2段所述条件的解释，不是支持。故错误。
D.没有质疑，故错误。

question_stem: Paragraph 3 answers all of the following questions EXCEPT
choices: tag: A
text: Why did the bolide fall to Earth?

tag: B
text: How fast was the bolide traveling?

tag: C
text: How was the bolide capable of generating a shock wave?

tag: D
text: How did the bolide cause flood damage to the Caribbean?
answer_key: A
explanation: 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 tremendous speeds carries an enormous amount of energy. When the bolide struck this energy was released and generated a huge shock wave.对应 C 选项。The impact displaced huge volumes of seawater, causing much flood damage in the Caribbean.对应 D 选项。A 选项为什么火流星会落向地球没有在原文中提及，所以选择 A 选项。

question_stem: Paragraph 3 strongly suggests that if the bolide impact theory is correct, the majority of the extinctions associated with the K-T event resulted from
choices: tag: A
text: sunlight being blocked for months by dust and smoke in Earth's atmosphere

tag: B
text: widespread flooding that followed the displacement of huge volumes of seawater

tag: C
text: the leveling of the landscape by the shock wave that was generated when the bolide struck Earth

tag: D
text: the rise in global temperatures caused by the fires that burned much of the landscape
answer_key: A
explanation: 根据原文 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. 可知 A 选项正确，太阳被地球大气的灰尘和烟挡住了。