1、如果先行詞是all, much, anything, something, nothing, everything, little, none等不定代詞,關(guān)系代詞一般只用that,不用which。如：

All that can be done has been done.
能做的都已經(jīng)做了 。
He will tell you everything that he heard about it.
他將告訴你他所聽到的關(guān)于這件事的一切。

2、當(dāng)先行詞被all, every, no, some, any, little, much所修飾時，只能用that，如：

There is little work that is fit for you.
沒什么工作運合你做。
I have eaten all the food that is left.
我把剩下的所有食物都吃了 。

3、先行詞是序數(shù)詞或最高級形容詞時，或者先行詞被序數(shù)詞（包括last，next)、最高級形容詞及the only, the very等修飾時。如：

This is the first film that I have seen since I came here.
這是我到這里后所看的第一場電影。
This is the best that has been used against pollution.
這是用來防止污染的最好辦法。
This is the very book that I am looking for.
這正是我一直在尋找的那本書。

4、先行詞包括人和物時，關(guān)系代詞應(yīng)該用that。如：

They often talk about the people and the things that they are interested in.
他們常常談?wù)撃切┧麄兏信d趣的人和事。
Luxun and his works that we are familiar with are considered great.
人們認(rèn)為我們所熟識的魯迅及其作品都很偉大。

5、當(dāng)主句是以who或which升頭的疑問句時，為了避免重復(fù)，多用that導(dǎo)。如：

Which is the house that caught fire last night?
昨晚失火的是哪座房子？
Who is the lady that is playing the piano?
在彈鋼琴的那位小姐是誰？

6、當(dāng)先行詞在定語從句中作表語時，只能用that。如：
This is a book that I have been looking for since last week.
這就是那本自上周以來我一直在尋找的書。

一、that與which的區(qū)別（只用that的情況）

當(dāng)先行詞指物時才需要討論這個問題

1. 當(dāng)先行詞為不定代詞，如anything, everything, nothing, none, one, all, little, few, much 等，或先行詞被all, little, few, much, any, only, the every, every, no等修飾時，要用that指代先行詞

• All that?is needed is oil.

• Finally, the thief handed?everyting that?he had stolen to the police.

• This is?the only problem that?remains to be settled.

2.?先行詞是序數(shù)詞/最高級形容詞時，或先行詞被序數(shù)詞，最高級形容詞修飾時，要用that

• This is?the first/best film?that I have seen since I came here.

3. 先行詞同時包括人和物時，要用that

• They often talk about?the people and the things?that they like most.

4. 避免重復(fù)

① 主句的主語是疑問詞who或which

• Which?is the bike?that?you have lost?

• Who?is the boy?that?won the gold medal?

② 兩個定語從句，其中一個用which另一個用that

• They secretly built up a small factory,?which?produced things?that?could cause much pollution.

5. 先行詞在主句中作表語,關(guān)系詞在從句中也作表語

• Shanghai is no longer the city?that?it used to be.

6. 主句是there be 句型且關(guān)系詞在從句中作主語

• There is?a seat?that?is still available.

即：限定性定語從句中，萬一腦抽無法判斷的時候，選that居多

二、不能用that的情況

1. 在非限定性定語從句中不能用that，而用who, whom,which等指代先行詞

• I saw Mary just now, who seemed very excited.

2.?介詞后不能用that

例：This is the person to whom your father spoke just now.

3. 當(dāng)先行詞是any, few, one(s), anyone, everyone, those, people等且指人時，只能用who, 不用that

• Those who are present will have the chance to see the film star.

4. 先行詞本身是that（避免重復(fù)）

5. there be結(jié)構(gòu)中先行詞指人

• There is a man who calls himself Mr. S joining our team.

以下是定語從句中用who不用that的情況:

1) 當(dāng)先行詞為人稱代詞?he, she, they 或one(s), anyone, nobody 等時
He who?plays a trick must be prepared to take a joke. 玩花招的人必定會受到戲弄。
The ones who?refuse to reform should be punished as required by law. 拒絕改革的人應(yīng)依法受到懲罰。
It was?she who?first introduced me to the pleasures of wine-tasting. 是她第一個讓我領(lǐng)略到品酒的樂趣。
There is?nobody who?has no shortcomings. 沒有缺點的人是沒有的。

2) 當(dāng)先行為指示代詞?those，或先行詞是those所修飾的人時
This website is dedicated to?those who?died in the war. 這個網(wǎng)站是獻(xiàn)給那些在戰(zhàn)爭中死去的人。
She is one of?those women who?always make the worst of their troubles. 她是那些老是把困難往最壞處想的女人之一。

3) 當(dāng)先行詞是序數(shù)詞或被序數(shù)詞修飾時
He is?the third man who?witnessed the murder. 他是這起謀殺案的第三個見證者。
They were?the first who?were there. 他們是去那里的第一批人。

4) 當(dāng)先行詞是 people 或是表示人的集體名詞時
An interactive product should show interest in?the people who?use it. 一款互動的產(chǎn)品應(yīng)該展現(xiàn)出對用戶的興趣。
The crew who?were all asleep forgot to hoist a lantern. 已入睡的船員全部忘了掛起提燈。

5) 當(dāng)先行詞與定語從句被其他句子成分隔開時。（更多這樣的例子可見隔離定語從句一文)
He is?the only doctor?in this hospital?who?I trust. 他是這家醫(yī)院里我唯一信得過的醫(yī)生。

6）當(dāng)關(guān)系代詞在從句中作主語且與謂語動詞被分隔開時
He was?a man who, if had been properly supported, would have worked wonders. 他是一個本該創(chuàng)造出奇跡的人，如果當(dāng)時給予適應(yīng)的支持的話。

7) 當(dāng)表示人的先行詞由兩個定語從句重疊修飾時(即雙重定語從句)，第二個定語從句只能用who/whom引導(dǎo)，而不能用that。而且第二個定語從句的引導(dǎo)詞不能被省略。
The only person I know who?has a skeleton in the cupboard is George Carlton. 我所認(rèn)識的唯一的在柜中藏骷嶁的人便是喬治. 卡爾頓。

當(dāng)先行為人時，定語從句的關(guān)系代詞一般情況下既可以用who/whom, 也可以用that，而且用who要比用that普遍。先行詞為人時，還有一些情況下只能使用who而不能用that，這些情況可看《定語從句用who不用that的情況》一文。那么，有沒有一些情況只能用that，而不能用who呢？答案是肯定的。下面就列舉一些需要我們注意的情形。

1) 在疑問句中，如果開頭的疑問代詞是who，為了避免重復(fù)，定語從句宜使用that引導(dǎo)而不用who, 如:
Who?is the hero?that?must thus be sacrificed? 誰是需要作出犧牲的英雄呢？
Who?is the scientist?that?first discovered radium? 首先發(fā)現(xiàn)鐳的科學(xué)家是誰？

2) 當(dāng)先行詞為疑問代詞who, which時，如:
We all realized?who that?remark was aimed at. 我們都知道那話是對誰而言的。
Which of us that?knows something about physics does not know this? 我們中但凡知道點物理知識的人哪一個不懂這個？

3) 當(dāng)關(guān)系代詞在定語從句中作表語或賓語補足語時，定語從句也不用who引導(dǎo)，而用that, 或者省略關(guān)系代詞。
He is no longer the man?that?he was. 他已經(jīng)不是過去的他了。(先行詞在定語從句中作表語）
He is not the fool?(that)?you thought him. 他不是你想像中的那個傻瓜。 (注：這條句子中 the fool 在定語從句中作賓語補足語，即 thought him the fool)

4) 當(dāng)先行詞同時包含人和物時
The bike and its rider that?had run over an old man were taken to the police station. 撞倒老人的車和事主已被帶到警局。

當(dāng)先行為人時，定語從句的關(guān)系代詞一般情況下既可以用who/whom, 也可以用that，而且用who要比用that普遍。先行詞為人時，還有一些情況下只能使用who而不能用that，這些情況可看《定語從句用who不用that的情況》一文。那么，有沒有一些情況只能用that，而不能用who呢？答案是肯定的。下面就列舉一些需要我們注意的情形。

1) 在疑問句中，如果開頭的疑問代詞是who，為了避免重復(fù)，定語從句宜使用that引導(dǎo)而不用who, 如:
Who?is the hero?that?must thus be sacrificed? 誰是需要作出犧牲的英雄呢？
Who?is the scientist?that?first discovered radium? 首先發(fā)現(xiàn)鐳的科學(xué)家是誰？

2) 當(dāng)先行詞為疑問代詞who, which時，如:
We all realized?who that?remark was aimed at. 我們都知道那話是對誰而言的。
Which of us that?knows something about physics does not know this? 我們中但凡知道點物理知識的人哪一個不懂這個？

3) 當(dāng)關(guān)系代詞在定語從句中作表語或賓語補足語時，定語從句也不用who引導(dǎo)，而用that, 或者省略關(guān)系代詞。
He is no longer the man?that?he was. 他已經(jīng)不是過去的他了。(先行詞在定語從句中作表語）
He is not the fool?(that)?you thought him. 他不是你想像中的那個傻瓜。 (注：這條句子中 the fool 在定語從句中作賓語補足語，即 thought him the fool)

4) 當(dāng)先行詞同時包含人和物時
The bike and its rider that?had run over an old man were taken to the police station. 撞倒老人的車和事主已被帶到警局。