I live a long way from work, as [which] you know. 我住得離工作單位很遠(yuǎn),這你是知道的。
1. 通常要用as的場(chǎng)合
?、佼?dāng)從句位于主句前面時(shí),只用 as。如:
As is known to everybody, the moon travels round the earth once every month. 月球每月繞地球轉(zhuǎn)一周,這是每個(gè)人都清楚的。
?、谟糜趕uch, as, the same后引導(dǎo)限制性定語(yǔ)從句時(shí),只能用as。如:
I never heard such stories as he tells. 我從未聽過(guò)他講那樣的故事。
This is the photo which shows my house. 這張照片拍的是我的住宅。
2. 兩者的細(xì)微區(qū)別
?、賏s引導(dǎo)的非限制性定語(yǔ)從句應(yīng)與主句在意義上和諧一致,which無(wú)此限制。如:
He went abroad, as [which] was expected. 他出國(guó)了,這是大家預(yù)料到的。
He went abroad, which was unexpected. 他出國(guó)了,這讓大家感到很意外。(不用as)
?、赼s引導(dǎo)非限制性定語(yǔ)從句時(shí),先行詞通常不能是主句中某個(gè)具體的詞,而應(yīng)是整個(gè)句子、整個(gè)短語(yǔ)或某個(gè)短語(yǔ)推斷出來(lái)的概念,而which 則無(wú)此限制。如:
The river, which flows through London, is called the Thames. 這條流經(jīng)倫敦的河叫泰晤士河。(不用as)
?、郛?dāng)as引導(dǎo)非限制性定語(yǔ)從句作主語(yǔ)時(shí),其謂語(yǔ)通常應(yīng)是連系動(dòng)詞,而不宜是其他動(dòng)詞,而 which則無(wú)此限制。如:
She has married again, as [which] seemed natural. 她又結(jié)婚了,這似乎很自常。
She has married again, which delighted us. 她又結(jié)婚了,這使我們很高興。(不用as)