语义的区别:当主句和从句语义一致时,用as;当主句和从句语义转折不一致时,用which。位置的区别:看到句首一定用as,which不可能放在句首。含义的区别:as有“正如”的含义,which没有此含义,否定句用which。
定语从句基本概念在复合句中,修饰某一名词或代词的从句叫定语从句。如:
Do you know the man who spoke at the meeting just now?
That is the house where he lived ten years ago.
定语从句所修饰的词叫先行词;定语从句一般用关系代词或关系副词来引导,关系词放在先行词与定语从句之间起连接作用,同时又作从句中的一个成分。
引导定语从句的关系代词有:that, who, whom, whose, which;
关系副词有:when, where, why.
关系词的用法(一)关系代词的用法:
1. 作主语用who, which和that, 如:
He is the man who/that lives next door.
The train which/that has just left is for Shenzhen.
2. 作宾语用whom, who, which, that, 如:
The man (whom/who/that) we have just seen is a famous writer.
Where is the book (which/that) I bought last week?
注:在非正式文体中,用于指人的关系代词who whom, that 通常可以省略,但在正式文体中通常用whom, 不可省略;用于指物的关系代词which和that 在非正式文体中也通常省略,但在正式文体中一般不省略。