定语从句

区别

例句

限制性定语从句中

名词前有such和the same修饰时，关系代词用as,不能用which

He is not such a fool as he looks.

Don’t read such books as you can’t understand.

非限制性定语从句中

as和which都可以指代前面整个主句。如果有“正如，象”的含义，并可以放在主句前，也可以放在后面，那么用as；而which引导的从句只能放主句后，并无“正如”的意思。

They won the game, as we had expected.

They won the game, which we hadn’t expected.

As is well known, he is a famous film star in the 1980s.

类别

语法意义及特征

例句

限制性定语从句

对先行词起修饰限制作用，如果去掉，主句意思就不完整明确，这种从句与主句的关系十分密切，写时不用逗号分开。

The accident happened at the time when I left.

非限制性定语从句　

对先行词作附加的说明，与主句的关系不十分密切，较松散。从句和主句之间用逗号分开，相当于一个插入语，不能用that引导，关系代词做宾语时也不能省略。

His mother, whom he loved deeply, died ten years ago.