第一种:关系代词引导的定语从句关系代词所代替的先行词是人或物的名词或代词,并在句中充当主语、宾语、表语等成分。关系代词在定语 从句中作主语时,从句谓语动词的人称和数要和先行词保持一致。1)who, whom, that这些词代替的先行词是人的名词或代词,在从句中所起作用如下:Is he the man who/that wants to see you?他就是想见你的人吗?(who/that在从句中作主语)He is the man whom/ that I saw yesterday.他就是我昨天见的那个人。(whom/that在从句中作宾语)2) Whose 用来指人或物,(只用作定语, 若指物,它还可以同of which互换), 例如:They rushed over to help the man whose car had broken down.那人车坏了,大家都跑过去帮忙。Please pass me the book whose cover is green.=Please pass me the book the cover of which is green.请递给我那本绿皮的书。3)which, that它们所代替的先行词是事物的名词或代词,在从句中可作主语、宾语等,例如:A prosperitywhich / thathas never been seen before appears in the countryside.农村出现了前所未 有的繁荣。(which / that在从句中作主语)The packagewhich / thatyou are carrying is about to come unwrapped.你拿的包快散了。(which / that 在从句中作宾语)4)but在句中作主语,在意义上相当于 who not或that not5)than一般用在形式为比较级的复合句中,其结构为形容词比较级(more)...than+从句第二种:关系副词引导的定语从句关系副词可代替的先行词是时间、地点或理由的名词,在从句中作状语。1)when, where,why关系副词when, where, why的含义相当于"介词+ which"结构,因此常常和"介词+ which"结构交替使用.There are occasions whe