限制性定语从句与非限制性定语从句

限制性定语从句与非限制性定语从句

2．关系代词which与as引导非限制性定语从句的区别。

（1）which与as都可以引导非限制性定语从句，which引导定语从句要置于先行词后面，而as引导的定语从句位置相对灵活，可放在句首，也可以放在句后

eg.正像他所意识到的那样，我对他非常有用

As he realized, I was very useful to him.

空气，众所周知，是一种气体

Air, as we know, is a gas.

他是个外国人，正像我从他口音判断的那样。

He was a foreigner, as I know form his accent.

他又来晚了，这一点使老板很生气

He came late again, which made his boss angry.

(2)当定语从句位于主句后面，纯粹表示主句所述的内容，往往用which；当定语从句中有“如同……那样”的含义时，用as比用which更常见。

Eg.妈妈老把我当成小孩对待，让我无法忍受

Mummy always treats me just like a baby, which I can’t bear.

事与愿违，这是常有的事

Things will turn out contrary to on e’s wishes, as is often the case.

(3)“介词+关系代词”结构的定语从句，必须用which,不能用as.

Eg.我们周围有很多氧气，没有他们我们无法生存

There is a great deal of oxygen around us, without which we could not live.

3．引导限制性定语从句时which与as的区别

定语从句前面有such, as, the same 时，引导定语从句的关系代词用as,不用which.

Eg 所需要的字典有许多都有了

There are as many dictionaries as needed.

他讲的那些故事我从没听过

I have never heard such stories as he tells.

我们正面临着和多年以前同样的困境

We are facing the same problems as we did years ago.