我们知道这道题的一个重要考点是平行结构。所以首先，我们要迅速找到句子中间用来建立并列关系的连词（在划线部分之后立刻出现的“and”）。

然后，我们发现紧跟在之后的部分是“the rest serve the colony by blah blah blah（直到句子结束）”。此时，我们可以判定，这个部分是一个结构完整的clause。

于是，通过平行结构的原则去找到整个题目中与这个clause形成并列关系的部分（注意：语法上，必须也是一个结构完整的clause；同时，内容上，需要能对应于与其形成并列关系的部分的主语“the rest”。这里是一个难点：同时满足语法和内容两个方面的要求）。

至此，我们得出正确答案：选项D。

我们把选项D带回题目中替换划线部分，然后把句子拆解如下：

【主句状语】：Like ants,

【主句主谓宾】：termites have an elaborate social structure

【主句宾语的定语】：形式为定语从句：in which a few individuals reproduce and the rest serve the colony by tending juveniles, gathering food, building the nest, or battling intruders.

定语从句内部：

【状语】：in which

【分句一】：a few individuals reproduce

【建立并列关系的连词】：and

【分句二】：the rest serve the colony by tending juveniles, gathering food, building the nest, or battling intruders

至此，我们明确找到了这个句子中平行结构：“A事件 and B事件”这个并列关系。这里，我们再次提醒大家注意平行结构中的难点：构成平行结构的并列关系中，A和B（甚至C、D）不仅仅要在语法上可以并列，还需要在内容上也可以并列。也就是说不仅仅要在语法上合理，还需要在内容上能说通。

好的，接下来我们再看一题：

While Noble Sissle may be best known for his collaboration with Eubie Blake, as both a vaudeville performer and as a lyricist for songs and Broadway musicals, also enjoying an independent career as a singer with such groups as Hahn’s Jubilee Singers.

A) and as a lyricist for songs and Broadway musicals, also enjoying

B) and writing lyrics for songs and Broadway musicals, also enjoying

C) and a lyricist for songs and Broadway musicals, he also enjoyed

D) as well as writing lyrics for songs and Broadway musicals, he also enjoyed

E) as well as a lyricist for songs and Broadway musicals, he had also enjoyed

这道题的正确选项C是不是很明显了？由both … and … 构成的平行结构，所以是“as both a vaudeville performer and as a lyricist”。简单明确。

好了，平行结构还有没有更复杂更困难的情况？在GMAT的SC部分中，当句子整个结构更加复杂的时候，平行结构在句中就会不那么容易被辨别。具体的情况，我们下一讲见。