定语从句中什么时候引导词只能用that不能用which，什么时候只能用which不能用that？求高手，

定语从句中什么时候引导词只能用that不能用which，什么时候只能用which不能用that？求高手，

当先行词是everything, anything, nothing （something 除外）, all, none, few, little, some等不定代词时，或当先行词受every, any, all, some, no, little, few, much等词修饰时。如：
Have you set down everything that Mr Li said?
There seems to be nothing that is impossible to him in the world.
注意： 当先行词指人时，偶尔也可用关系代词who。如：
Any man that / who has a sense of duty won’t do such a thing.
All the guests that / who were invited to her wedding were important people.
2. 当先行词被序数词修饰时。如：
The first American movie that I watched was the Titanic.
3. 当先行词被形容词最高级修饰时。如：
This is the best museum that I have visited all my life.
4. 当先行词被the very, the only, the first / last等修饰时。如：
She is the only person that understands me.
After the big fire, the old car is the only thing that he owns.
注意： 当先行词指人时，偶尔也可以用关系代词who。如：
Wang Hua is the only person in our school who will attend the meeting.
5. 当先行词前面有who, which等疑问代词时。如：
Who is the man that is standing in front of the crowd?
Which is the room that Mr Wang lives in?
6. 当先行词为人与动物或人与物时。如：
Look at the man and his donkey that are walking up the street.
7. 当先行词是reason, way（方法）等词时，关系代词常用that代替in which, for which, why, 也常可省略。如：
She admired the way （that） they solved the questions
非限制性定语从句就是用逗号隔开的句子，只能用which

1）不用that的情况 a) 在引导非限定性定语从句时 (错) the tree, that is four hundred years old, is very famous here. b) 介词后不能用 we depend on the land from which we get our food. c)多用who 的情况 ①关系代词在从句中做主语 a friend who helps you in time of need is a real friend . ②先行词为those , people 时 those who were either fools or unfit for their offices could not see the cloth . ③先行词为all, anyone , ones , one 指人时 one who doesn’t work hard will never succeed in his work . ④在there be句型中 there is a stranger who wants to see you . ⑤在被分隔的定语从句中 a new teacher will come tomorrow who will teach you german . ⑥在有两个定语从句的句子中，其一用who,其二用that,但若先行词后接两个以上的并列定语从句时，后一个必须重复前一个关系代词。 the student who was praised at the meeting is the monitor that is very modest and studies very hard . there is a teacher who is always ready to help others and who enjoys what he does .

that 可修饰人和物，which只能修饰物，当句子主句为人可用that，当句子主句为物，可用which或that，当句子主句有带that的宾语从句必须用that