【例4】 While the men worked to strengthen the dam, the rain continued to fall; and the river, which was already well above its normal level, rose higher and higher.
【分析】这是由两个分句(用冒号连接)组成的并列句，各个分句都有自己的从句，所以是一个复合句。第一个分句中有一个while引导的时间状语从句，第二个分句中有一个which引导的非限制性定语从句。其主干就是：The rain continued to fall and the river rose higher and higher,其他都可以看成是附加成分。
复合句是由一个主句和一个或一个以上的从句构成。主句是全句的主体，从句必须由关联词引导(有时可以省略)，是附属成分，但有自己的主语和谓语部分。例如：When I got there they had left for Shanghai.这句话中主句是they had left for Shanghai，从句是when I got there。
【例10】We may define chemistry as the science in which we deal with the chemical change in matter as a result of which it is possible to form a new substance.
【分析】该句中的两个which都是定语从句的先行代词，第一个代替science,第二个代替哪个单词呢?正常而言，应该是matter,但事实上代替chemical change。如果你将matter置于从句中，没有因果关系(as a result of)，所以只能是chemical change。
【译文】我们可以把化学定义为关于物质化学变化的科学，化学变化可能会形成新的物质。
【例11】Mike told her the story of the young pilot which I narrated at the beginning of this book.
【分析】此句中的the young pilot 把which与其先行词story分割开，因为如果先行词是pilot，则不能用which代替，只能用who或that。
【例12】He is just the type I always knew would attract her. (省略主语的复合定语从句)
【译文】我一向知道他正是会吸引她的那种类型。
或：他正是我一向知道的会吸引她的那种类型。
【分析】该句有三个谓语部分，即一个系表结构、knew和would attract,但没有任何连接词，所以可以判断是省略了两个连接词。仔细研究，可知：I always knew would attract her是一个省略掉主语that的复合定语从句，其中I always knew 应该是that would attract her的一个定语从句，完整的句子应该是：He is just the type that that I always knew would attract her。第一个that既是复合定语从句的先行代词，也是复合定语从句的主语，还是其内部定语从句that I always knew的先行词。因为第二个that在定语从句I always knew中做宾语，所以会省略掉;而第一个that是复合定语从句的主语，也可以省略，但在正式文体中一般不省略。例如：
【例13】It was a discovery that scientists said could alter their theories about life’s earliest beginnings. (未省略主语的复合定语从句)
【分析】该句有三个谓语部分，即：一个系表结构、said和could alter,但只有一个连接词that,所以应该省略了一个连接词。经研究，可知that scientists said could alter their theories about life’s earliest beginnings是一个复合定语从句，that是先行代词，也是主语(未省略)，还是其内部的一个定语从句scientists said的先行词;同时，由于scientists said的先行代词that在定语从句中做宾语，所以可以省略。