1.指人的關係代詞：who, whom, whose, that 的用法：
(1)作主語(who, that )
Those who are going to play in the match are to meet at the gate at 1:30 after lunch. 那些參加比賽的人午飯後1：30在大門口集合。
在本句中，先行詞是those;關係代詞who引導定語從句，同時代替先行詞在從句中擔任動詞are going to play 的主語。
The man who/that is talking with Mr. Wang is a famous doctor. 正在和王先生說話的那個人是一個有名的醫生。
在本句中，先行詞是the man;關係代詞who/that引導定語從句，同時代替先行詞在從句中擔任動詞is talking的'主語。
這個複合句可以還原成兩個句子：The man is a famous doctor. He is talking with Mr. Wang.
(2)作賓語包括作介詞賓語(whom, that )。此種情況下的關係代詞可以省略;
This is just the man(whom/that) I want for the job.這正是我要的做這份工作的人。
在本句中，先行詞是the man;關係代詞whom/that 引導定語從句，同時代替先行詞在從句中擔任動詞want 的賓語。
(3)當關系代詞緊跟介詞作介詞賓語時，不能用that，也不能省略，
如：The book from which I got a lot of useful information was written by a famous scientist.
我從中得到許多有用資訊的那本書是一位著名科學家寫的。
但是當介詞放在從句末尾時，作為介詞賓語的關係代詞可以用that 並且可以省略。
如上頭兩句可改為：
The book (that /which) I got a lot of information from was written by a famous scientist.
2.指物的關係代詞which和that的用法：
(1)作主語
This is the instruction manual which/that tells you how to operate the computer. 這是那本教你如何操作計算機的說明手冊。
(2)作賓語包括作介詞賓館。此種情況下的關係代詞可以省略：
The chair (which /that) you broke yesterday is now being repaired. 你昨天弄壞的那把椅子現在正在修理。
The accounts of the company, (which/that) I’ve been paying great attention to, are in balance.
我一直非常注意的公司賬目，是保持平衡的。
e 和of which 指代人或事物，作定語。of which 可用whose 代替; The car whose lights (of which the lights/the lights of which) were all broken was my father’s.
那輛所有的燈都破了的汽車是我父親的。
That is the book whose cover (of which the cover/the cover of which ) was broken. 這就是那本封皮破了的書。
4.關係代詞的格應與它在從句中充當的成分一致。特別要注意插入語，
如：Peter is the one who everybody believes will fail to bring off the contract. Peter 是那個人人都認為不能完成合同的人。(everybody believes 是插入語) At the election I voted for the man whom I believed to be the most suitable. 在選舉的時候我投了我認為最合適的那個人的票。
5.關係代詞作從句的主語時，從句的動詞必須和先行詞的人稱和數一致： 例：These are the operating instructions that/which are written in English 。 這就是用英文寫成的使用說明。
6.非限定性定語從句不用that，只用who(whose, whom)和which代表人和物; 例：Her brothers, both of whom work in America, ring her up every week。 她的兄弟們兩個人都在美國工作每個星期都給她打電話。
7.關係副詞(=介詞+關係代詞)： 關係副詞 先行詞 在從句中的作用 說明 when(=at / on / in /during which),非正式文體中，有時用that代替關係副詞
