托福阅读修辞目的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阅读中考察的修辞目的题及其对应的解析，供大家参考使用。本文带来的是TPO15-2的修辞目的题，一起来看看吧。
TPO15-2 Mass Extinctions
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.
10. In stating that no asteroid itself has ever been recovered the author emphasizes which of the following?
The importance of the indirect evidence for a large asteroid
The fact that no evidence supports the asteroid- impact hypothesis
The reason many researchers reject the Alvarez hypothesis
The responsibility of scientists for not making the effort to discover the asteroid itself
解析：修辞目的题，看本句先，原句说Ir异常支持了撞击说，但还没发现具体的星体。所以B说没有evidence错，说反了;C有人reject他的观点，还有D的scientists的责任原文都没说，不选;正确答案是A，只有Ir异常这个间接证据就可以支持撞击说，所以是indirect evidence
[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。
paragraph 7
An asteroid of this size would be expected to leave an immense crater, even if the asteroid itself was disintegrated by the impact. The intense heat of the impact would produce heat-shocked quartz in many types of rock. Also, large blocks thrown aside by the impact would form secondary craters surrounding the main crater. To date, several such secondary craters have been found along Mexico's Yucatan Peninsula, and heat-shocked quartz has been found both in Mexico and in Haiti. A location called Chicxulub, along the Yucatan coast, has been suggested as the primary impact site.
12.What is the purpose of paragraph 7 in the passage?
It proposes a decisive new test of the Alvarez hypothesis.
It presents additional supporting evidence for the Alvarez hypothesis.
It explains why evidence relating to the Alvarez hypothesis is hard to find.
It shows how recent evidence has raised doubts about the Alvarez hypothesis
解析：问整段的题关注头尾，开头说撞击会留下大坑，又说热量blabla，结尾说某某地方被认为是撞击发生的地方，所以应该是支持撞击理论，所以B的additional supporting evidence正确;D的doubts不对;C说撞击位置很难找到与最后一句相反，错;A的test原文没说
[7]按理说，这样大小的一个行星，即使受到冲击碎裂之后也会留下一个巨大的陨石坑。撞击所释放的极度高温使得许多种岩石产生热冲击石英。撞击也会将一些大石块抛出去，在主要陨石坑周围形成次级陨石坑。迄今为止，人们沿着墨西哥尤卡坦半岛已经找到了一些此类次级陨石坑。并且在海地和墨西哥找到了热冲击石英。尤卡坦沿海一个叫做希克苏鲁伯的地方，曾被认为是主要的撞击点。
以上就是托福阅读TPO15-2中的修辞目的题及其解析，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。
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