非限制性定语从句知识点（三）

非限制性定语丛句中as, which的区别：

1、which引导非限制性定语从句代表前面的整个句子的时候，一般是对主句的结果的说明。 
        如： He grows too fast, which makes him taller than his classmates. 
        2、as引导非限制性从句代表前面整个句子时一般来讲从句的谓语动词有三种： 
        A. 含有be动词：
        如：He failed the exam, as is natural. 
        B. 实意动词的被动形式： 
        如：As is reported, the fire caused a great loss. 
        C. 感官动词和意识类动词如：
        如：see, hear, notice, know, learn, realize 等。 
        As you know, I am a teacher. 
        3、as可翻译为正如，它引导的丛句可位于主句之前，也可位于主句之后；which引导的该丛句只能位于主句之后。
        例1：__A___he realized, I was very useful to him. 
        例2：This elephant is like a snake, ___A__anybody can see. 
         A. As(as)
         B. which
         C. that
         D. who