定语从句的引导词有哪些?怎样使用?

定语从句是在复合句中修饰某一名词或代词的从句.被修饰的名词或代词叫做选行词,
而引导定语从句的词叫引导词,有关系代词和关系副词两类.
1． 关系代词有：that,which,who,whom,whose,在定语从句中作主语、宾语中表语,whose
作定语.代人的有：who,whom,whose,that；代物的有：that,which,whose.例如：
The man who helped you is Mr White.(who代人,在定语从句中作主语)
That is the person(whom/who/that) you want to see.(whom,who,that代人,在定
语从句中作宾语,可省略)
I?m not the fool(that) you thought me to be.(that代人,在定从中作表语)
A dictionary is a useful book which(＝that) tells us the meaning of words(which
或that代物,在定从中作主语)
2． 关系副词有：when(指时间),where(指地点),why(指原因),在定语从句中作状语.
例如：Would you suggest a time(when) we can have a talk?(when可省略)
The house where they live is not very large./This is the reason why he did not came to the meeting.
注意：不是表时间的先行词都用when引导定从,不是表地点的先行词都用where引导定从.