关系代词which,that,who的区别which VS that which和that都可指代物，有时候可以互换，有时却是“水火不容”： 一、只用that不能用which的情况： (1)先行词被序数词或形容词较高遥所修饰，或本身是序数词、基数词、形容词较高遥时： The most important thing that we should do is to study hard.
我们要做的较重要的事情就是努力学习。
(2)被修饰的先行词为all/ any/ much/ many/ everything/ anything/ none/the one等不定代词时： Is there any thing that you want to buy?
你有什么东西要买吗?
(3)先行词被the only/ the very/ the same/the last/ little/ few等词修饰时： This is the same book that I lost.
这就是我丢的那本书。
(3)先行词里同时含有人和物时： I can remember the persons and some pictures that I saw in the room.
我能清楚记得我在那个房间所见到的人和一些照片。
(4)避遥重复： Which is the pen that belongs to you?
哪支笔是你的?
(5)主句是there be结构： There is a pen on the desk that belongs to Tom.
桌子上那支笔是汤姆的。
二、只用which，而不用that的情况： (1)先行词为that/ those时： What’s that which is under the desk?
在桌子底下的那些东西是什么?
(2)关系代词前有介词时： This is the city in which he lives.
这是他生活的城市。
(3)引导非遥遥定语从句： Tom passed the exam, which made us surprised.
汤姆通过了考试，这使我们很惊讶。
that VS who 两者均可指人，有时可互换： All that /who heard the news were sad.
所有听到消息的人都很伤心。
He is the only one among us that/ who knows Spanish.
他是我们中间遥懂西班牙语的人。
一、只用that不能用who的情况： (1)遥行词指人又指物时： I remember the persons and pictures that I saw in the museum.
我记得在博物馆看到的那些人和图片。
(2)避遥重复：： Who was it that won the World Cup in 1982?
谁赢得了1982年的世界杯?
(3)当关系代词在定语从句中作表语时(可省略)： Jack is not the boy (that) he was ten years ago.
杰克不再是十年前那个样子了。
二、只用who不能用that的情况: (1)先行词为one、ones或anyone ： Anyone who breaks the law should be punished.
所有违法的人都该受到惩罚。
(2)先行词为those且指人 ： Those who break the law will be punished.
违法的那些人都会受到惩罚。
(3)在there be开头的句子中： There is a student who wants to see you.
(4)避遥重复： Who is the boy that is writing?
正在写字的那个男孩是谁?
(5)在非遥遥定语从句中: I have a good friend, who comes from the USA.