定语从句

介词+which/whom引导的定语从句用于正式场合。在这一结构中，关系代词which/whom做介词的宾语。

1. 当先行词是人时，用介词+whom引导定语从句，此时不用who或that。 例如：

They may start as a group of high-school students, for whom practising their music in someone’s house is the first step to fame.

The person to whom I lent my bicycle is Mr. Ball.

The girl with whom my sister visited the Great Wall has just come back from London. 

2. 当先行词是物时，用介词+which引导定语从句，而且只能加which，不能加that。例如：

They produced a new record in 1996,  with which they  celebrated their former time as a real band.

The prize for which he worked so hard was a new bike.

The house to which he took us was very old. 

注：含有介词的短语动词一般不拆开，介词仍放在动词后面，不提前，如：look for, look after, take care of等。例如：

This is the watch which he was looking for.（T）

This is the watch for which he was looking.（F）

The babies whom the nurses are looking after are healthy.（T）

The babies after whom the nurses are looking are healthy.（F）