首先明白引導定語從句的as屬於關係代詞,在定語從句中作名詞成分。
as引導非限定性定語從句與which的區別是,(1)as翻譯成「正如,正像」 which翻譯成「這,那=and this/that」 (2) as引導的定語從句可以放句中,句首,句末。
As we realized,English is important for us.
Air,as we know,is a gas.
He was a teacher,as can be seen.
She has married again,which was unexpected.
常見的有as we all know,as has been said above,as has been pointed out等
as引導限定性定語從句必須與前面the same,so,such,as等構成一個結構。
There are as many dictionaries as are needed. 所需要的詞典都有了
He is such a good teacher as we all like. (定語從句)
對比:
He is such a good teacher that we all like him. (結果狀語從句)
另外注意the same…that表示相同,thesame…as表相似
I have the same pen as you have.
This is the same pen that I lost yesterday.
I have never heard such stories as he tells.
He lifted so heavy a stone as no one else can lift.
有時通用
The meeting was put off,as/which was exactly what we want.
He was a doctor,as/which I knew from his manner.