.英语定语从句用法详解在复合句中 , 修饰名词或代词的从句叫定语从句 , 被修饰的名词或代词叫先行词 , 引导定语从句的有关系代词 who, whom, whose, which, that等和关系副词where, when, why等 , 关系代词和关系副词在定语从句中担任句子成份。 1.由who引导的定语从句中 , who用作主语 , 如 : This is the boy who often helps me. 2.由whom引导的定语从句中,whom用作宾语,如:The man whom you are waiting for has gone home. 3.由whose引导的定语从句中 , whose用作定语 , 如 : Do you know the girl whose skirt is white? 4.由which引导的定语从句中,which用作主语或谓语动词的宾语或介词的宾语,如: The room in which there is a machine is a work shop. The river which is in f