省略

省略主语：

当并列成分是由同一个主语发出，并列连接词后可以省略主语：

She came forward and shook hands with me

省略谓语 ：

当连接词后面两个分句中的谓语动词相同时候，后一分局中谓语可以省略

I'd like to come but i can't

省略其他成分：

The boy wanted to bring his chest to the shopping center alone, but his mother told him not to

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，可同时省略从句的主语和be 动词的某种形式

when while 引导的时间状语从句：

Be confident of success when (you are) running the company

If , unless , once 引导的条件状语从句：

If (it is ) properly educated, child will become confident.

Once (you are) caught cheating in an exam, you will be punished

Though, although, whether, no matter when / what/how/who 等引导的让步状语从句：

He was happy, though (he was) poor.

As if, as though 引导的方式状语从句

He rubbed his eye and yawned as if (he was) waking up after a long sleep.

than as 引导的比较状语从句中的省略

当不同的主语进行比较，一般可以省略从句中的谓语；当从句中的主语与谓语和主语中的主语与谓语相同时，通常省略从句中的谓语，只保留比较部分

He is taller than his brother(is)

 

关系代词 that, which , whom 等在限制性定语从句中充当宾语且部位与介词之后时，可以省略。

The man (that/ who / whom) you visited last night is my grandpa.

 

当条件状语从句中有were，had，should 等时，省略if。把他们提到句首，形成倒装

If I were a teacher, I would be strict with my students.

Were I a teacher, I would be strict with my students.

 

 

参考

https://zhuanlan.zhihu.com/p/67310478