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�0�7m 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。