3) －It is going to rain, isn't it?

－I hope not. (it is not going to rain.)

这种用法常见的有：How so? Why so? Is that so? I hope so. He said so.　及I suppose　/believe　/hope not. Why not?等等。

2.宾语从句中的省略

宾语从句中常省略连词that，但当有两个并列的宾语从句时，第二个that则不能省略。

1) We all know (that) the earth runs around the sun.

2) Mary said (that) she is from American and that she is 16 years old.

3. 定语从句中的省略

在定语从句中，that, which, who在从句中作宾语时可省略。

1) I haven't read the book (that/ which) you're reading.

2) The man (that/ who) your father just talked to is our English teacher, Mr. Smith.

4. 状语从句中的省略

在以when, while, once引导的时间状语从句及以if, unless引导的条件状语从句中和though, although引导的让步状语从句中，如果从句中的主语与主句中的主语

指同一对象，且从句中含有be动词时，从句中可省去"主语+be"部分。

1) When he was asked what he had done, John just kept silent.

 When ( he was )asked what he had done, John just kept silent.

2) If he is free, Jack will go with us.

 If (he is) free, Jack will go with us.

3) Unless he is invited, he won't come.

 Unless ( he is) invited, he won't come.

4) While he is doing house work, my father often listens to music.

 While ( he is) doing house work, my father often listens to music.

四 不定式中的省略

动词不定式中为了避免重复，省去与前面出现的相同部分，只保留to，但如果在省略的不定式结构中含有be，have, have been时，要保留这些词。

1) -Are you going there?

- Yes, I'd like to .(go there).

2) He didn't give me the chance, though he had promised to . (give me the chance).

3) -Are you an engineer? - No, but I want to .(be)

4) -He hasn't finished the task yet.

-Well, he ought to .(have)

Attention !

使役动词及感官动词后面作宾语补足语的不定式一定要省去to,但在被动语态中须将to复原

1) I noticed a man to enter the classroom when I passed by.

----- A man was noticed to enter the classroom.

这类使役动词及感官动词主要有:

一感feel, 二听listen to ,hear, 三让have ,make ,let,四看notce ,see ,watch ,observe

五 虚拟条件句中的省略