省略 （Ellipsis）
(1) 并列复合句中某些相同成分的省略。
Boys like sports, while girls don’t.(like sports)
(2) when , while , before, after , if, as if , though, until , whether 引导的状语从句的主语和主句的主语相同；或主语是it,谓语为be动词，主语和be 同时省略。
When heated, water is turned into vapor.
If possible, you can help us do something.
(3) 在than , as , no matter what, who等分句后。
You are taller than he.(is)
Anyone, no matter who(he is), can point out our mistakes.
(4) 在know , think , consider, suppose, find, believe, say, decide等词后的宾语从句常省略that。
I think (that) it will be fine this afternoon.
(5) whom, which, that在定语从句中作宾语时；所有进行时态的定语从句，可省略关系代词和be动词，只用现在分词；所有被动式的定语从句，省略关系代词和be 动词，只用过去分词。
The boy sitting in the corner is my brother.
I saw a girl dressed in blue.
(6) 有形式主语it的主语从句可省略that。
It is the third time (that) I have come to China.
(7) direction , way, distance, time, times 后的定语从句省略that, which, in which
The direction you move is wrong.
I don’t like the way you speak to your parents.
(8) 祈使句；感叹句；部分疑问句省略主语、谓语。
What a big classroom( it is) !
Close the door please.
Why not?
(9) so , neither, nor , not 倒装时句子要省略。
——I went to town yesterday.
-----So did I.(=I went to town yesterday, too.)
(10) 某些动词后的宾语补足语或主语补足语可省略to be。
They found the answer ( to be) correct.
(11) “the more…. the more…” 句型中可省略be或there be。
In studying English, the more practice, the better.
(12) 虚拟语气中条件句省略if或主语从句、表语从句、宾语从句或同位于从句省略should.
Had I had time yesterday, I would have come to help you.
We suggested that he (should) go to see a doctor at once.