托福阅读事实信息题是阅读考试中比较常见的一种题型，tpo则是托福阅读备考最权威的材料，所以托福小编综合二者，为大家集中整理了tpo阅读中考察的事实信息题及其对应的解析，供大家参考使用。本文带来的是TPO15-2的事实信息题，一起来看看吧。
TPO15-2 Mass Extinctions
Paragraph 1:
Cases in which many species become extinct within a geologically short interval of time are called mass extinctions. There was one such event at the end of the Cretaceous period (around 70 million years ago). There was another, even larger, mass extinction at the end of the Permian period (around 250 million years ago). The Permian event has attracted much less attention than other mass extinctions because mostly unfamiliar species perished at that time.
1.Paragraph 1 supports which of the following statements about mass extinctions?
A. They take place over a period of 70 million years.
B. They began during the Cretaceous period.
C. They eliminate many animal species that exist at the time they occur.
D. They occur every 250 million years.
解析：以mass extinctions做关键词定位至第一句，说大量生物在短时间内灭绝的这种现象叫做大灭绝事件，C是原文的同义替换，所以是正确答案。70 million和250 million是两次大灭绝事件发生的时间，不是A说的七千万年一直在发生，也不是D说的每2500万年发生一次;B的began和原文的end是反的，错
【1】地质年代中，在一个短期的时间间隔有大量物种灭绝的现象就被称为大规模物种灭绝。在白垩纪时期后期(大约七千万年前)就曾经发生过一次大规模物种灭绝。而在二叠纪时期后期(大约两亿五千万年前)还发生过一次规模更大的物种灭绝。由于当时灭绝的物种很少为人类所知，所以二叠纪时期的大规模物种灭绝受到的关注远远不如其他几次大规模物种灭绝。
Paragraph 2:
The fossil record shows at least five mass extinctions in which many families of marine organisms died out. The rates of extinction happening today are as great as the rates during these mass extinctions. Many scientists have therefore concluded that a sixth great mass extinction is currently in progress.
2.According to paragraph 2, scientists base their belief that a mass extinction is going on at present on which of the following?
The speed with which mass extinctions are happening today is similar to the speed of past extinctions.
The number of species that have died out since the last extinction event is extremely large.
Mass extinctions occur with regularity and it is time for another one.
Fossil records of many marine species have disappeared.
解析：以at present做关键词定位至最后一句，但这段很短，快速扫完后两句之后就有答案，说现代生物灭绝的速度和大灭绝的时候差不多，得出大灭绝现在正在发生，所以原因是灭绝速度相似，答案A
【2】化石记录显示，历史上至少发生过五次大规模物种灭绝，造成大批海洋生物消亡。如今物种灭绝的比率和之前五次大规模物种灭绝时期一样高。因此许多科学家推断：当前，第六次大规模物种处于灭绝状态。
Paragraph 3:
What could cause such high rates of extinction? There are several hypotheses, including warming or cooling of Earth, changes in seasonal fluctuations or ocean currents, and changing positions of the continents. Biological hypotheses include ecological changes brought about by the evolution of cooperation between insects and flowering plants or of bottom-feeding predators in the oceans. Some of the proposed mechanisms required a very brief period during which all extinctions suddenly took place; other mechanisms would be more likely to have taken place more gradually, over an extended period, or at different times on different continents. Some hypotheses fad to account for simultaneous extinctions on land and in the seas. Each mass extinction may have had a different cause. Evidence points to hunting by humans and habitat destruction as the likely causes for the current mass extinction.
5.Paragraph 3 supports which of the following ideas about mass extinctions?
Scientists know the exact causes of most mass extinctions.
Mass extinctions are unlikely to happen again in the future.
Insects, flowering plants, and bottom-feeding predators in the oceans tend to be the first organisms to disappear during episodes of mass extinctions.
Some mass extinctions occurred on land and in the seas at the same time.
解析：问全段的，最好用排除法。A的exact causes做关键词定位至前两句，原文说有很多假设，所以没有准确原因，A错;B的future原文没说，所以错;C的一大堆生物做关键词定位至第三句，但原文没说它们是最先遭殃的一群生物，C错;D的land and seas做关键词定位至倒数第三句，simultaneously就是at the same time，正确
【3】是什么原因引起如此高的物种灭绝率呢?有几种假说，包括：地球变暖或变冷;季节型波动的改变或洋流变化;大陆位置移动。生物假说包括因昆虫与开花植物之间的合作式进化或海洋底层肉食动物进化引起的生态变化。这些生物机制，有些在极短的时间内就会灭绝，而有些则很有可能经过长时期在不同时代或不同大陆缓慢地进行。有些假说未能解释在陆地和海洋同时发生的物种灭绝。可能每次大规模物种灭绝都有不同的原因。但有证据指出，人类狩猎以及人类破坏栖息地很可能是当前大规模物种灭绝的原因。
paragraph 4:
American paleontologists David Raup and John Sepkoski, who have studied extinction rates in a number of fossil groups, suggest that episodes of increased extinction have recurred periodically, approximately every 26 million years since the mid-Cretaceous period. The late Cretaceous extinction of the dinosaurs and am monoids was just one of the more drastic in a whole series of such recurrent extinction episodes. The possibility that mass extinctions may recur periodically has given rise to such hypotheses as that of a companion star with a long-period orbit deflecting other bodies from their normal orbits, making some of them fall to Earth as meteors and causing widespread devastation upon impact.
7. According to paragraph 4, what aspect of extinction episodes does the companion-star hypothesis supposedly clarify?
¡ Their location
¡ Their frequency
¡ Their duration
Their severity
解析：以companion star hypothesis做关键词定位至最后一句，说mass extinction的反复发生支持了companion star hypothesis，这个hypothesis说轨道变形导致一些星体偏离正常轨道，成为陨星掉入地球，原句说屡次发生，所以能够解释extinction的频率，答案是B
【4】美国古生物学家David Raup 和 John Sepkoski 曾经从大量化石群中研究物种灭绝的比率。他们指出，自从白垩纪时期中期以来，灭绝的物种不断增多，大约每隔两千六百万年就会定期发生一次。白垩纪时期后期的恐龙和菊石(的灭绝是一系列此类周期性物种灭绝中更为剧烈的一次。对于周期性出现大规模物种灭绝的可能性，引发了这样的假设：一颗具有长周期轨道的伴星体使其他天体从正常轨道偏离，导致其中一些天体变成流星掉落到地球，撞击时造成大范围破坏。
paragraph 6:
One interesting test of the Alvarez hypothesis is based on the presence of the rare-earth element iridium (Ir). Earth' s crust contains very little of this element, but most asteroids contain a lot more. Debris thrown into the atmosphere by an asteroid collision would presumably contain large amounts of iridium, and atmospheric currents would carry this material all over the globe. A search of sedimentary deposits that span the boundary between the Cretaceous and Tertiary periods shows that there is a dramatic increase in the abundance of iridium briefly and precisely at this boundary. This iridium anomaly offers strong support for the Alvarez hypothesis even though no asteroid itself has ever been recovered.
9. According to paragraph 6, what made iridium a useful test of the Alvarez hypothesis?
¡ Its occurrence in a few locations on Earth against several locations on other planets
¡ Its occurrence in limited quantities on Earth against its abundance in asteroids
¡ Its ability to remain solid at extremely high temperatures
¡ Its ease of detection even in very small amounts
解析：以人名做关键词定位至第一句，但第一句没说为什么铱测试对验证A的假说很有用，往下看，说地球上Ir几乎没有，但其他星体含量多很多，同义改写的答案是B。也就是说如果地球上发现大量Ir，就说明遭受过撞击
【6】Alvarez 假说基于稀土元素铱的出现做了一个非常有趣的实验。这种元素在地壳中的含量极少，但在大多数小行星中的含量却多得多。因小行星碰撞而被抛进到大气中的碎片可能会含有大量铱元素，并且大气流会把这些物质带到全球各地。白垩纪时期与第三纪时期交替之间的沉积物的研究显示：在这两个时期的交替时期，铱元素的含量急剧增加。尽管还没有发现过撞击的小行星，铱元素异常却为Alvarez假说提供了有力支持。
以上就是托福阅读TPO15-2中的事实信息题及其解析，大家可以在备考的时候参考复习，希望能够帮助大家的考前准备。最后前程百利祝大家都能取得理想的托福考试成绩。
您还可能关注：
