关系代词as与which的用法区别(1) 引导限制性定语从句时，在such, as, the same后只能用as，其他情况用 which：I never heard such stories as he tells.

我从未听过他讲那样的故事。

It’s the same story as I heard yesterday.

这故事跟我昨天听到的一样。

This is the photo which shows my house.

这张照片拍的是我的住宅。

(2) 引导非限制性定语从句时，有时两者可互换：I live a long way from work, as [which] you know.

我住得离工作单位很远，这你是知道的。

(3) 但在，在以下情况引导非限制性定语从句时，两者不可换用：① 当从句位于主句前面时，只能用 as：As is known to everybody, the moon travels round the earth once every month.

月球每月绕地球转一周，这是每个人都清楚的。

② as 引导的非限制性定语从句应与主句在意义上和谐一致，which无此限制：He went abroad, as [which] was expected.

他出国了，这是大家预料到的。

He went abroad, which was unexpected.

他出国了，这让大家感到很意外。

(不用as)③ as 引导非限制性定语从句时，先行词通常不能是主句中某个具体的词，而应是整个句子、整个短语或某个短语推断出来的概念，而which 则无此限制：The river, which flows through London, is called the Thames.

这条流经伦敦的河叫泰晤士河。

(不用as)④ 当as 引导非限制性定语从句作主语时，其谓语通常应是连系动词，而不宜是其他动词，而 which则无此限制： She has married again, as [which] seemed natural.

她又结婚了，这似乎很自然。

She has married again, which delighted us.

她又结婚了，这使我们很高兴。

(不用as)【关系代词as与which的用法区别查看网站：[db:时间]】