菜鸟求救英语（高分）~~~关系代词what who which whom 的区别极其用法

what是特殊疑问代词主要问物品.what is it.who是问人的.who is it.which在范围内选择.there are two pen ,which is mine.whom主要是问谁的whom is the pen.

这些都是从句问题,一般可省略,很简单,只要你弄清楚什么时候用哪个就行了,至于到底是定语从句,状语从句,宾语从句的一般考卷上不会考的,
举例:
一, who指人，在从句中做主语
1,The boys who are playing football are from Class One.
2,Yesterday I helped an old man who lost his way
二,whom指人，在定语从句中充当宾语，常可省略。
1, Mr. Liu is the person (whom) you talked about on the bus.
2, Mr. Ling is just the boy whom I want to see.
三 that指人时，相当于who或者whom；指物时，相当于which。在宾语从句中做主语或者宾语，做宾语时可省略。
1,The number of the people that/who come to visit the city each year rises one million.
2Where is the man that/whom I saw this morning?
四which指物，在定语从句中做主语或者宾语，做宾语时可省略
1 Football is a game which is liked by most boys.
2 This is the pen (which) he bought yesterday.