1. 当先行词为all,much,little,none及由any, every,some,no所构成的复合不定代词时。
例如: We should do all that is useful to the people.
Please tell me anything that you know about the matter.
2当先行词被 any, few, little,no,a,much,some等词修饰时。例如:
You can take any seat that is free.任何空着的座位你都可以坐。
There is little work that is fit for you.几平没有适合你的工作。
When people talk about the cities of China. the first that comes to my mind is Beijing.人们谈论起中国的城市的时候，我首先想到的是北京。
This is the fourth film that has been shown in our school this term.
例如: The best that I could do was to apologize. 我唯一能做的就是赔礼道歉了。
This is the most interesting story book that I have ever read.
5. 当先行词被 the very, the only, the last, the just, the same等修饰时。
例如: This is the very book that I'm looking for.
The only thing that we could do was to wait.
注意：先行词被 the same修饰时，关系代词也可用as。
例如: I need the same book that/as you have.我需要有你一样的书。
例如: They are talking of the heroines and their deeds that interest them.
例如: Who that has ever worked together with him doesn't admire him?
Which is the planet that is nearer to the earth?
例如:That's a good book that will help you a lot.那是本对你很有帮助的书。
Our school is no longer the place that it used to be.
例如: I do remember the first time(that) I had ever heard the sweetest voice in the world.
I did’t remember the exact time when/that)I arrived in Shanghai last month.
1. 在“介词+关系代词”结构中，关系代词必须用 which
例如: The house in which we live is very large.我们住的房子非常大。
This is the reference book of which the teacher is speaking.
例如: This is the question which/that we’ve had so much discussion about=This is the question about which we’ve had so much discussion.
例如. You should grasp well those skills which may be used in the future work.你应该掌握以后在工作中用到的技能。
如: She likes the child for the very reason that(-for which )she loves his father.她喜欢那个孩子因为她爱着孩子的父亲。
He didn't like the way that(in which) she speaks to his mother.
Imagine the speed that (=at which) he drives the car.
The reason( that /for which /why ）he came here was to ask for our help.