定语从句中介词加关系代词的用法

“介词+关系词”的用法 1、关系代词在从句中作介词的宾语时，介词常可以提前，但介词提前时，关系代词只能用which 或 whom。 如：The school (that/which) he once studied in is very famous. →The school in which he once studied is very famous. Tomorrow I will bring here a magazine (that/which) you asked for. →Tomorrow I will bring here a magazine for which you asked. We'll go to hear the famous singer (whom/that/who) we have often talked about. →We'll go to hear the famous singer about whom we have often talked. 2、关系副词when, where, why 和介词+which之间的关系。 关系副词when, where, why可以用适当的介词+which来替代。介词的位置非常灵活，有时放在关系代词之前，有时放在动词之后。如：when=in/on/at…+which,    where=in/on/at…+which,    why=for+which 如：I won’t forget the date when( on which) I was born. This is the room where (in which) I lived. = This is the room which I lived in. I don’t know the reason why (for which) he hasn’t come today. Tom still remembers the days when (in which) they lived in Tianjin.  注意： 1). 含有介词的动词短语一般不拆开使用，如：look for, look after, take care of等 如：This is the watch which/that I am looking