托福阅读细节题的出题解析

　　了解了句群的概念，还有另外一个问题需要解决。其实，细节题考察文章中的具体内容，但是又要给大家一定的障碍，不至于一眼看出答案，这时候，ETS要经过一个同义改写的过程，即改变表述方式，但是意思还是那个意思。

　　有了句群和同义改写这两个基本概念，就可以说明托福阅读细节题的出题过程了：在托福阅读文章中抽取一个句群，然后改变这个句群的表述方式，得到一个新的句群;然后把新句群分成两份，一份作为题干，一份放在四个选项中备选。

　　举个例子看一下：

　　Paragraph 1: It should be obvious that cetaceans—whales, porpoises, and dolphins—are mammals. They breathe through lungs, not through gills, and give birth to live young. Their streamlined bodies, the absence of hind legs, and the presence of a fluke1 and blowhole2 cannot disguise their affinities with land dwelling mammals. However, unlike the cases of sea otters and pinnipeds (seals, sea lions, and walruses, whose limbs are functional both on land and at sea), it is not easy to envision what the first whales looked like. Extinct but already fully marine cetaceans are known from the fossil record. How was the gap between a walking mammal and a swimming whale bridged? Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.

　　1. In paragraph 1, what does the author say about the presence of a blowhole in cetaceans?

　　○It clearly indicates that cetaceans are mammals.

　　○It cannot conceal the fact that cetaceans are mammals.

　　○It is the main difference between cetaceans and land-dwelling mammals.

　　○It cannot yield clues about the origins of cetaceans.

　　解析：首先，找到题干中的关键词去锁定出题所涉及的句群。关键词是a blowhole，找到句子(句群)Their streamlined bodies, the absence of hind legs, and the presence of a fluke1 and blowhole2 cannot disguise their affinities with land dwelling mammals.除了题干中的句群部分the presence of a blowhole in cetaceans之外，句群中的剩余部分是：cannot disguise their affinities with land dwelling mammals，意思是“不能不能掩饰它们和陆生哺乳动物的相似之处”看选项，选项B明显是可以表达这一个意思的，它就是这部分剩余内容的同义替换。

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