vi. 关系代词but, what

1. but作为关系代词常与具有否定或疑问意义的主句连用，其引导的从句修饰的先行词多是否定意义的，but=who ... not/which ... not/that ... not，意为“无不/没有不/谁不”。

There's no one but knows the importance of English.

没有不懂得英语重要性的人。

Not a single room in this hotel but is empty.

这个宾馆没有一个房间不是空的。

2. who ... but（=that ... not）意为“谁不……的？”

Who is there but makes some mistakes？

Who is there that does not make any mistakes?

人哪有不犯错误的？

3. what引导定语从句时既可指人也可指物，指人时what=the person(s) that，指物时what=the thing/all/everything that。

That is exactly what he told me.

that is exactly The thing he told me.

那正是他告诉我的。

4. what本身的作用已经包含有先行词和关系代词。有一身兼两职的作用，分别在主句和从句中作相应的成分。

Don't do what you shouldn't do.

不要做你不应该做的事。

Never pretend to know what you really don't know.

不要假装知道你并非真正知道的事情。

5. 用what时，前无先行词；若有先行词，应视其情况选择使用that, which，或who。

What can be done has been done.

能做的都已经做了。

All that can be sold has been sold.

所有能卖的都已经卖了。

I have known everything that you want to tell me.

我已经知道了你想告诉我的一切。

专项练习

1. Generally speaking, there is no one _______ loves their parents in the world.

A. that

B. but

C. who

D. A or B or C

2. All _______ is needed is a supply of oil.

A. the thing

B. that

C. what

D. which

3. _______ is over is over.

A. What

B. That

C. What all

D. All what

4. _______ were once truth are true no longer.

A. What

B. That

C. Which

D. All

5. _______ you have done might do harm to other people.

A. That

B. What

C. Which

D. This

6. A computer can only do _______ you have instructed it to do.

A. how

B. after

C. what

D. whom

7. They want to know _______ do to help us.

A. what can they

B. what they can

C. how they can

D. how can they

8. This is the longest train _______ I have ever seen.

A. which

B. that

C. what

D. whom

9. Who studies here _______ wants to go to college?

A. that

B. but

C. who

D. whom

10. There's none of us _______ wishes to go to Tsinghua University.

A. but

B. that

C. who

D. which

答案速查　1-5　BBAAB　6—10　CBBBA