關系代詞as與which在用法上的區別與辨析

一、引導限制性定語從句時的區別

在such, as, the same后只能用as，其他情況用which。如：

You must show my wife the same respect as you show me. 你必須對我妻子表現出與對我同樣的敬重。

He’s not such a good writer as he’s cracked up to be. 他并不像人們所吹捧的那樣是什么杰出的作家。

The Commission will take as long as is deemed necessary to make its decision. 委員會將用其認為必要長的時間來作出決定。

二、引導非限制性定語從句時的區別

引導非限制性定語從句時，有時兩者可互換。如：

I live a long way from work, as [which] you know. 我住得離工作單位很遠，這你是知道的。

但在，在以下情況引導非限制性定語從句時，兩者不可換用：

①當從句位于主句前面時，只用as。如：

As is usual with children, they soon got tired. 孩子們一貫如此, 他們很快就厭倦了。

As I have already mentioned, I doubt that we will able to raise all the money we need. 正如我早就說過的，我懷疑我們是否能夠籌集到足夠的資金。

As is often the case with children, Amy was completely better by the time the doctor arrived.  就像經常發生在兒童身上的情況一樣，醫生趕到時，埃米的病情徹底地好轉了。

②as引導的非限制性定語從句應與主句在意義上和諧一致，而which則無此限制。如：

She married him, as [which] was natural. 她嫁給了他，那是自然的事。

She married him, which was disgraceful. 她嫁給了他，那是很丟人的。(不用as)

③as引導非限制性定語從句時，先行詞通常不能是主句中某個具體的詞，而應是整個句子、整個短語或某個短語推斷出來的概念，而which則無此限制。如：

The government, which promises to cut taxes, will be popular. 這個政府，它保證要減稅，將會是得人心的。

The lawyers are preparing for the trial, which commences in 30 days. 律師們正在為這場將于30天后開始的審判進行準備。

The new bourgeoisie, which was created by the Industrial Revolution, had money to spend and wanted to travel. 工業革命產生的新興資產階級有了閑錢就想出去旅游。

④當as引導非限制性定語從句作主語時，其謂語通常應是連系動詞，而不宜是其他動詞，而which則無此限制。如：

She has married again, as [which] seemed natural. 她又結婚了，這似乎很正常。

She has married again, which delighted us. 她又結婚了，這使我們很高興。(不用as)