定语从句中，只能用，which，且不用that：
1、引导非限制性定语从句时，当关系词前有介词时。
2、在一个句子中有两个定语从句，其中一个定语从句的关系代词用了that, 另一个应用which。
3、当关系代词后面有插入语时。
4、先行词为that时。
拓展资料
which
1. He lived on an invalidity pension which came as a weekly giro.
他靠每周领取的作为病残养老金的直接转账救济支票过日子。
2. Politicians want a lap-dog press which will uncritically report their propaganda.
政客们想要的是不问是非、甘为他们搞宣传的哈巴狗一样的新闻媒体。
3. We were in the same college, which was male-only at that time.
我们那时在同一所学院，当时只招男生。
4. We gained a rich supply of data which would normally be inaccessible.
我们得到了通常难以获取的大量数据。
5. "Which one of these do you want?" — "I don't mind."
“你想要这里面的哪一个？”——“都可以。”
6. A formal contract is signed which is renewable annually.
正式签订了每年可续签的合同。
7. He was already asleep in the bed, which smelled faintly of mildew.
他已经在略带霉味的床上睡着了。
8. Show me which one you like and I'll buy it for you.
指给我看你喜欢哪个，我给你买。
9. Why not retrain for a job which will make you happier?
为什么不接受新的培训，找一份让你更快乐的工作？
that
1. A miracle is something that seems impossible but happens anyway.
奇迹就是看似不可能，却发生了。
2. If you wait, all that happens is that you get older.
如果你等待，发生的只有变老。
3. When life gets hard and you want to give up, remember that life is full of ups and downs, and without the downs, the ups would mean nothing.
当生活很艰难，你想要放弃的时候，请记住，生活充满了起起落落，如果没有低谷，那站在高处也失去了意义。
4. Eventually, you'll learn to cry that on the inside.
终有一天，你会学会让泪往心里流。
5. Success is not final, failure is not fatal: it is the courage to continue that counts.--Winston Churchill
成功不是终点，失败也并非末日，最重要的是继续前进的勇气。
6. It's not about making the amazing saves. It's the little things and small things that made great gatekeepers great.
伟大的门将不是靠神奇的扑救成就，而是靠注重小事和细节成功。（Tim Howard美国国家队门将）
7. The turning point in the process of growing up is when you discover the core of strength within you that survives all hurt.
当你从内心深处找到一种可以忍受一切痛苦的坚强力量时，你的成长历程就会出现飞跃。
1.引导非限制性定语从句时，eg:
She is an artist，which I am not. 她是一位艺术家，而我不是。
2.当关系词前有介词时，
Bejing is the place in which i was born.
北京是我出生的地方。
该句中的in which=where
3.在一个句子中有两个定语从句，其中一个定语从句的关系代词用了that, 另一个应用which。
Let me show you the novel that I borrowed from the library which was newly open to us. 我来给你看我从新开的图书馆里借来的那本小说。
that引导的从句修饰先行词the novel，which引导的定语从句修饰先行词the library.
4.当关系代词后面有插入语时
Here is the English grammar which, as I have told you, will help improve your English. 这就是我跟你说过的会有助于提高你英语的那本英语语法书。
as I have told you是插入语
5.先行词为that时
The clock is that which can tell us the time. 钟是报时的装置。
该句也可以换成名词性从句"The clock is what can tell us the time."追问
什么是非限制性定语从句，
追答非限定性定语从句，起补充说明作用，缺少也不会影响全句的理解，在非限定性定语从句的前面往往有逗号隔开，如若将非限定性定语从句放在句子中间，其前后都需要用逗号隔开。
This novel，which I have read three times，is very touching.
这本小说很动人，我已经读了三遍。
非限制定语从句中是不是有逗号，所以都用which
追答which引导非限制性定语从句的情况居多，其它的关系代词引导非限制性定语从句的也有。在非限定性定语从句中，who, whom代表人，用which代表事物。
Mr. Li , who was my former teacher, retired last year.
李老师去年退休了，他曾经是我的老师。
是不是一个句子中有逗号就不可能用，that
追答不能笼统地这样说，只是在非限定性定从中不能用。
追问合力方向怎么画
本回答被提问者采纳1、 在介词后面的关系代词用which而不能用that。即“介词+which（代物）” 。
例句：
The building in which Han Mei studied was very old.
韩梅在里边学习的那幢大楼很旧。
2、 在非限定性定语从句中用which，不能用that。
例句：
Crusoe's dog, which was very old now, became ill and died.
克鲁索的狗，现在已经很老了，病死了。
3、有两个定语从句，其中一个关系代词已有which，另一个宜用that。相反，如果其中一个为that，另一个宜用which。
例句：
Let me show you the novel that I borrowed from the library which was newly open to us.
让我给你看看我从新开放的图书馆借来的小说。
4、描述句中一般用which。
例句：
Beijing，which was China's capital for more than 800years.
北京是中国800多年来的首都。
5、those +复数名词之后，多用which 。
例句：
Shopkeeper want to keep a number of those goods which sell best.
店主想保留一些卖得最好的商品。
1、非限制性定语从句中。
e.g. Mary has a book, which is very precious.
2、在介词之后。
e.g. This is a house in which lives an old man.
3、当主句中的主语被that修饰时。
e.g. That dog which I found in the street belongs to Mary.追问
什么是非限制性定语从句，
追答定语从句有限制性和非限制性两种。限制性定语从句是先行词不可缺少的部分，去掉它主句意思往往不明确；非限制性定语从句是先行词的附加说明，去掉了也不会影响主句的意思，它与主句之间通常用逗号分开，将非限定性定语从句放在句子中间，其前后都需要用逗号隔开。
These apple trees，which I planted three years ago，have not borne any fruit.
这些苹果树是我三年前栽的，还没有结过果实。
This is the mountain village (which) I visited last year.
非限制定语从句中是不是有逗号，所以都用which
追答不是因为有逗号，有逗号是非限定性定语从句的标志。
追问是不是一个句子中有逗号就不可能用，that
追答可以那么理解。
本回答被网友采纳.
.
.
.
当定语从句，作宾语时，只能用which 不能用that追问
什么是非限制性定语从句，
追答限制性定语从句：
限制性定语从句对先行词起限制、修饰的作用，关系代词有that,which,whom,who,whose以及关系副词when,where等，没有明显的逗号把从句与主语分开，表达的意思为被修饰词的一个定语。
例句：
Do you know the professor who is speaking at the meeting?
Where is the book which I bought this morning?
非限制性定语从句：
作用相当于一种插入语或者对先行词的一种解释，和先行词之间只有比较松散的关系，文字中常常用逗号将其与主句分开，用法其实与限制性定语从句极为相似，只是不能用that做修饰词。
例句：
This letter is from his parents, who are working in Tibet.
Englishi is an important subject, which every students should study well.
The building, in front of which sat a boy, was a school.
一、
定语从句有限制性和非限制性两种。限制性定语从句是先行词不可缺少的部分，去掉它主句意思往往不明确；非限制性定语从句是先行词的附加说明，去掉了也不会影响主句的意思，它与主句之间通常用逗号分开，例如：
This is the house which we bought last month. 这是我们上个月买的那幢房子。（限制性）
The house, which we bought last month, is very nice.这幢房子很漂亮，是我们上个月买的。（非限制性）
2) 当先行词是专有名词或物主代词和指示代词所修饰时，其后的定语从句通常是非限制性的，例如：
Charles Smith, who was my former teacher, retired last year. 查理·史密斯去年退休了，他曾经是我的老师。
非限制定语从句中是不是有逗号，所以都用which