1 关系代词who（whom）的用法1．who 可以代人（即它的先行词必须是人），在从句中可以担任主语，往往也可以代替在从句中担任宾格的whom，但它的前面不能有介词，如果带介词则必须用宾格的whom： 介词+whom。
She is the girl with whom I went there.
（因为把介词with 提到从句的前面了，所以只能够用whom，而不能用who 来代替）
2．在本章开始处所列的表格中可以看出who, that 在许多情况下可以通用，但有时则宜用who，而不用that。
a．先行词是one, ones, anyone 时宜用who。
One who has nothing to fear for oneself dares to tell the truth.
The ones who flatter me don’t please me.
Don’t tell anyone about the news who oughtn’t to know it.
anyone 只能指人，用who 较合适，但是先行词本身是anything 时，
则宜用that 为关系代词，另外这句中先行词anyone 与定语从句中间有一些别的词则更宜用who 作为关系代词。
Anyone who fails to finish the task given should be criticized.
b．先行词为those 时，宜用who 为关系代词。
Those who were not fit for their work could not see the
beautiful clothes made of the magic cloth.
Those who want to go to the Great Wall sign up here.
I met a foreigner in the street yesterday who could ask me
question in Chinese.
The boy that you met last night is the group leader who studies very hard.
e．在there be 开头的句子中
There is an old man who wants to see you.
There are many young men who are against him.
3 关系代词that 的用法1．首先要特别注意that 只能用在限定性定语从句中，在非限定性定语从句中永远不能选用that，另外介词后面不能跟that，而跟which。
Crusoe’s dog, which was very old now, became ill and died.⋯（○）
Crusoe’s dog, that was now very old, became ill and died.⋯(×)
2．在限定性定语从句中which 和that 在代替物时，一般可以通用。
The money that (which) is in the wallet is mine.
The money that (which)（省略）my mother gave me yesterday has been stolen.
This is the best that has been used against pollution.
English is the most difficult subject that you will learn during these years.
He is the last person (that) I want to see.
It is the first American m ovie of this kind that I’ve ever seen.
c．主句已有疑问词who 或which 时。
Which is the bike that you lost?
Who is the woman that was praised at the meeting?
Do you know the things and persons that they are talking about?
The bike and its rider that had run over and old man were taken to the police station.
e．先行词是all, much, little, something, everything, anything,nothing, none, the one 等代词时。
You should hand in all that you have.
We haven’t got much that we can offer you.
I mean the one that you talked about just now.
f．先行词前面only, any, few, little, no, all, one of, the same,the very 等词修饰时。
The only thing that we can do is to give you some money.
Li Ming is the only one that got full marks in our class.
Li Ming is the only one that wants to be a teacher.
Li Ming is one of the students that want to be teachers in our class.
Edison built up a factory which produced things that had never been seen before.
4 关系代词which 的用法1．在非限定定语从句中，只宜用which，不能用that。
Beijing, which is the capital of China, is a very beautiful city.
Li Ming is late for school every day, which makes his teacher very angry.
2．在限定性定语从句中which 和that 在代物时常常可以通
This is the hotel in which you will stay.
=That’s the hotel (which/that/可省略) you will stay.
Let me show you the novel that I borrowed from the library which was newly open to us.
that 和which 在定语从句中作关系代词的主要区别