限定性定语从句
一、关系代词（在句中作主语、宾语或定语）
1.that既可代表事物也可代表人,which代表事物；它们在从句中作主语或宾语,that在从句中作宾语时常可省略关系词,which在从句中作宾语也可以省略.[eg：this is the book （which）you want.]
2而且,如果which在从句中作“不及物动词＋介词”的介词的宾语,注意介词不要丢掉,而且介词总是放在关系代词which的前边,但有的则放在它原来的位置
3.代表物时多用which,但在带有下列词的句子中用that而不用which,这些词包括当先行词是anything,everything,nothing ,none等不定代词时,或者是由every,any,all,some,no,little,few,much等修饰时等,这时的that常被省略 还有先行词前有序数词或形容词最高级修饰时,或先行词就是序数词或最高级时.以及先行词中既有人又有物时.还有句中前面有which时,都只能用that
4.who和whom引导的从句用来修饰人,分别作从句中的主语和宾语,whom作宾语时,要注意它可以作动词的宾语也可以作介词的宾语
5.whose是关系代词,修饰名词作定语,相当于所修饰成分的前置所有格.它引导的从句可以修饰人和物,当它引导的从句修饰物体时,可以与 of which 调换,表达的意思一样.
二、关系副词（在句中作状语）
关系副词=介词+关系代词
why=for which
where=in/ at/ on/ ...which (介词同先行词搭配)
when=during/ on/ in/ ...which (介词同先行词搭配)
1.where是关系副词,用来表示地点的定语从句.
2.when引导定语从句表示时间〔注〕值得一提的是,表示时间“time"一词的定语从句只用when引导,有时不用任何关系代词,当然也不用that引导.
By the time you arrive in London,we will have stayed there for two weeks.I still remember the first time I met her.Each time he goes to business trip,he brings a lot of living necessities,such as towels,soap,toothbrush etc.
3.当从句的逻辑主语是some,any,no,somebody,anybody,nobody,something,anything,everything或nothing时,常用there is来引导
There is somebody here who wants to speak to you.这里有人要和你说话.
