关系代词
•1、关系代词用来引导定语从句。它代表先行词，同时在从句中作一定的句子成分，例如：
The girl to whom I spoke is my cousin.跟我讲话的姑娘是我表妹。（该句中whom
既代表先行词the girl，又在从句中作介词to的宾语。）
2、关系代词有主格，宾格和属格之分，并有指人与指物之分。在限定性定语从句中，that
可指人也可指物，见表：
•例如：
This is the pencil whose point is broken. 这就是那个折了尖的铅笔。
(whose 指物，在限定性定语从句中作定语)
He came back for the book which he had forgotten.他回来取他丢下的书。
（which指物，在限定性定语从句中作宾语，可以省略）
★关系代词的用法
1、关系代词的句法功能
1）关系代词在句中作主语
例如：I prefer music that/which has great lyrics
2）关系代词在句中作宾语
例如：I like music that I can sing along with.
3）关系代词在句中作表语
例如：The house is not the one (that) it used to be.
2、关系代词在从句中作名词的定语
例如：Is she the teacher whose hair is very short?
3、关系代词的用法
1）who和whom的用法：二者都用于指人。Who在定语从句中作主语、宾语，whom 在定语从句中作宾语。Whom在从句中能坐介词的宾语，而who则不能。
例如：I happened to meet the professor (who/whom) I got to know at a party
in the shopping center yesterday.
2）whose的用法：一般指人，有时也指物。在定语从句中作定语。
例如：I have got a friend whose brother is training for the Olymoics.
3）which的用法：一般指物，在定语从句中作主语、宾语、偶尔作定语。
例如：The photo which we liked best was taken by Zhao Min.
4）that的用法：指人或物，指人时可与who、whom互换，指物时可与that互换。在从句中可作主语、宾语，还可作表语。
例如：It is a book (that/which) no one really likes.
4、用who不用that的情况
1）先行词是指人的不定代词时
例如：Congratulations to our winners and thanks to everyone who entered
the competitions.
2）先行词指人并含有较长的后置定语或在被分割的定语从句中时
例如：The boy was crying hard who lost his way while looking for his mother.
3）用在there be结构中。
例如：There is a young man who wants to see you.
4）避免重复或引起歧义。
例如：The man that spoke at the meeting is our new headmaster who has just come from Shanghan.
5）当先行词是I, you, he, they等时（常用语谚语之中）。
例如：He who plays with fire gets burned.
6）先行词如是指成员的集体名词，关系代词也用who。
例如：The family, who live upstairs, are fond of music.
7）先行词如是拟人化名词，关系代词也可用who。
例如：You will see the worker ants,who gather food for themselves and for all the others. 8）先行词指特定的人时，关系代词多用who，不指特定的人时多用that。
例如：The aunt who came to see us last week is my father’s sister.
People that have not been properly trained can’t do this kind of qork.
5、在以下情况中，关系代词用that
1）先行词为all, little, few, none 及some-, any-, no-与thing所组成的复合单词时，只能用that。
例如：There is nothing that will stop us making progress.
2）先行词前有only, some, any等形容词修饰时，只能用that。
例如：This is the only problem that we can’t work out.
3）先行词前由形容词的最高级或序数词修饰时，只能用that。
例如：This is the most interesting book that I have ever read.
4）先行词同时包括人和物时，只能用他和她，
例如：Lu Xun and his works that we are familiar with are considered great.
6、只能用which不能用that的情形
1）当非限制性定语从句中的先行词指物时，只能用which
例如：The pencil-case, which I bought last week, is missing.
2）关系代词前面有介词时，只能用which
例如：The tree under which we used to take a rest has been cut down.
3）先行词本身就是that时
例如：I don’t like that which he did.
