定语从句的引导词辨析which what that whom whose where 都在什么条件下面使用给几个例子就更

定语从句的引导词辨析
which what that whom whose where 都在什么条件下面使用给几个例子就更好了,不要怕麻烦

关系代词that：指物,有时也指人,在从句中作主语或宾语,作主语不可省略,做宾语可省略（在非正式文体中）eg:the boy that helped me is my brother.the building that we built last year is very tall.
关系代词which:指物,不指人,比that正式,在从句中作主语或宾语,作主语不可省略,做宾语可省略（在非正式文体中）.eg:the coat (which/ that) i put on the desk is black.
关系代词whom：指人,在从句中作宾语.eg:everyone loves the girl whom we call Mary.（此处亦可用who/ that/省略）
关系代词whose：在从句中作定语,不可省.eg:everyone loves the girl whose watch is new.
关系副词where：在从句中作状语.eg:my wife wants to go to the city where we knew each other.( where= in which)
what不引导定语从句,所以在定语从句中不能用what代替that.因为that是关系代词而what是连接代词,相当于the things that/ which...,也就是说what包含that.eg:do the students understand what you said?= do the students understand the words that you said?