状语从句中的省略用法
than，as引导的比较状语从句中的省略用法
Ⅰ、以if从句为代表的状语从句中的特殊省略用法
Ⅱ、定语从句中的省略用法
Ⅲ、虚拟语气中if及should的省略
Ⅳ、不定式符号to的省略
Ⅴ、So和not的替代性省略
Ⅵ、日常交际中的省略
省略句用法专项练习

Ⅰ、状语从句中的省略用法
一、如果从句的主语和主句的主语一致，且从句的谓语含有be动词的某种形式(am/is/are/was/were)，可同时省略从句的主语和be动词的某种形式。
1、when，while引导的时间状语从句
e.g. Do be careful when (you are) crossing the street.
When/While (I was) on my way to work, I met her.
2、if，unless，once引导的条件状语从句
e.g. If (it is) properly treated, waste will do no harm to the environment.
I’ll not go to the party unless (I am) invited.
Once (you are) caught stealing in a supermarket, you will be punished.
3、though，although，whether，no matter whether/what/how/who等引导的让步状语从句
e.g. He was happy, though/although (he was) poor.
Whether (she is) sick or well, she is always cheerful.
No matter how/However hard the task (is), we must fulfill it in time.(注：从句的主语和主句的主语不一致时，只省略从句中的be动词形式)
4、as if，as though引导的方式状语从句
e.g. He rubbed his eyes and yawned as if/though (he was) waking up after a long sleep.
He stood up as if/though (he wanted) to leave.(as if/though + to do表示一个将来的动作)
二、than，as引导的比较状语从句中的省略用法：
当不同的主语进行比较时，一般省略从句中的谓语;当从句中的主语与谓语(be动词除外)和主句中的主语与谓语相同时，通常省略从句中的主语和谓语，只保留比较部分。
e.g. He is taller than his brother (is).
I have as much as confidence in you as (I have confidence) in him.
三、以if从句为代表的状语从句中的特殊省略用法：通常省略了it is，that is，there is/are。
e.g. If (it is) possible/necessary, this old temple will be rebuilt.
If (that is) so, I will call you back at 5:00 pm.
There are only a few books in our school library, if (there are) any.
Ⅱ、定语从句中的省略用法
关系词的省略 关系代词that，which，whom等在限制性定语从句中充当宾语且不位于介词之后时，可以省略;in which或that在先行词way后作方式状语从句时可省略。
e.g. The man (that/who/whom) you visited last night is my grandpa.
I don’t like the way (in which/that) you treat the girl.
Ⅲ、虚拟语气中if及should的省略
1、当条件状语从句中有were，had，should等时省略if，把它们提至句首，形成倒装句。
e.g. If I were a teacher, I would be strict with my students.
= Were I a teacher, I would be strict with my students.
2、Suggest，insist，order，require等表示建议、要求、命令的动词后接的名词性从句中，谓语动词常用“should+动词原形”，should可以省略。
e.g. The doctor suggested that he (should) try to lose weight.