利用转折及让步分析句子丨美国留学,美国留学微信公众号文章

在讲到如何分析托福的长难句句子时，我们已经谈到了利用句中的并列连词、表因果关系的连词以及利用标点来分析句子。今天我们来谈一下如何利用句子中表转折关系或让步关系的词来分析句子。

首先，我们需要知道句子中有哪些词是表示转折或让步关系的。常见的表示转折关系的词及短语有but、however、instead of、rather than、on the contrary、in contrast、yet、nevertheless等等。表示让步的词及短语有though、although、even though、while、despite、in spite of等等。

其次，我们需要知道转折和让步都表示什么样的关系。转折关系是指前后信息相反，例如：I like that movie, but my sister doesn’t. 让步关系则是指从句中的信息固然是存在的，但主句信息更为重要，例如：Although I studied hard, I failed the exam.

最后，我们来看一下托福阅读中的相关题目。

例1：If the pores are large, the water in them will exist as drops too heavy for surface tension to hold, and it will drain away; but if the pores are small enough, the water in them will exist as thin films, too light to overcome the force of surface tension holding them in place; then the water will be firmly held.

我们先通过标点（上句中的分号）可以把句子先分成两个部分，接着我们可以看见后一部分中有表示转折的连词but。这时我们来看一下选项：

A. Surface tension is not strong enough to retain drops of water in rocks with large pores but it strong enough to hold on to thin films of water in rocks with small pores.

B. Water in rocks is held in place by large pores and drains away from small size pores through surface tension.

C. Small pores and large pores both interact with surface tension to determine whether a rock will hold water as heavy drops or as a thin film.

D. If the force of surface tension is too weak to hold water in place as heavy drops, the water will continue to be held firmly in place as a thin film when large pores exist.

通过对比选项我们可以看出，选项B和C中分别用“and”和“both……and”表示并列关系而文章中的句子表示的为转折关系，所以排除B和C；选项D为条件句，句中没有比较large pores和small pores，因而不选D。A选项既有表示转折关系的词也对比了large pores和small pores，所以选A。

例2：The whale retained a tail and lacked a fluke, the major means of locomotion in modern cetaceans. The structure of the backbone shows, however, that Ambulocetus swam like modern whales by moving the rear portion of its body up and down, even though a fluke was missing.

通过标点我们可以在“even though”之前把句子分成两个部分并能找出作为插入语的“however”。需要注意的是，本句中虽有表示转折关系的“however”，但在这里表示本句和上一句之间的转折关系。如果去掉“however”并不影响本句的分析。除去“however”，句中的“even though”表示让步关系。这时再来比较选项：

A. Even though Ambulocetus swam by moving its body up and down, it did not have a backbone.

B. The backbone of Ambulocetus, which allowed it to swim, provides evidence of its missing fluke.

C. Although Ambulocetus had no fluke, its backbone structure shows that it swam like modern whales.

D. By moving the rear parts of their bodies up and down, modern whales swim in a different way from the way Ambulocetus swam.

选项中只有A和C有让步关系，而A选项主句中说到该生物没有“backbone”与文章相反，所以本题选C。