英语中，为了避免重复，省略句子中的一个或几个成分，这种语法现象叫做"省略"。常见的省略现象有：
一、部分句子成分的省略
1. 省略主语。如：
(I) Beg your pardon.
2. 省略谓语。如：
(Is there) Anything you want?
3. 省略宾语。如：
-Where has Jim gone?
-Sorry, I don't know (where he has gone).
4. 省略主语和谓语（或谓语的一部分），只剩下表语、宾语、状语或其它成分。如：
What a pity (it is) you can't go to the lecture!
-What does he want to eat?
-(He wants) Some rice and vegetables.
(I'm) Glad to see you.
(Is it) Right?
二、主从复合句的省略情况
1. 状语从句的省略。有两种情况：
第一种情况：省略从属连词及从句中的主语和助动词，只保留分词作状语。如：
(If it is) Taken into a warm room, a piece of ice will turn into water.
(If they had been) Given more attention, the trees could have grown better.
第二种情况：省略从句中的主语及系动词或助动词，保留从属连词及表语。如：
When (he was) rescued, he was almost dead.
Jim made a lot of friends while (he was) working there.
If (it is) possible, I should like to get there today.
She hurried away as if (she was) angry.
2. 名词性从句的省略。如：
Tom has gone home, but I don't know why (he has gone home).
3. 在"the + 比较级......，the + 比较级......"句型中的省略。如：
The more practice (there is), the better (it is).
三、不定式省略
通常是保留不定式符号to，省略其后的实义动词。常见的有三种情况：
1. 系动词（be）+形容词，即be afraid / ready / glad / happy / willing等后面接不定式时：
-Could you go shopping with me?
- I'm glad to (go shopping with you).
2. mean, try, want, would like, would love, afford等后面接不定式时：
-Did you get a ticket?
-No, I tried to (get one), but there weren't any left.
3. tell, warn, order, advise, ask等动词后接不定式作宾语补足语时：
The students want to enter the lab, but the monitor advises them not to (enter the lab).
注意：在see, watch, hear, feel, observe, notice, look at, listen to等感观动词及使役动词后的"宾语+动词不定式作宾语补足语"的结构中，不定式符号to须省略，但这类结构变成被动语态时，其后的不定式要还原加上to。如：
I haven't told you that my family made a lot of money in the nineteenth century by making children work 16 hours a day in their factories.
The children were made to work more than 16 hours a day.
四、虚拟语气的省略
1. 在含有if的虚拟条件句中可省去if，而把助动词had, should, were提到句首构成倒装。如：
Should it (If it should) rain tomorrow, we would have to put off the visit to the Yangpu Bridge.
2. 在suggest, insist, order, demand, advise等后的宾语从句中，谓语动词用should+动词原形，其中的should可省去。如：
The doctors suggested that she (should) not smoke.
He ordered that all (should) take part in the work.
I advised that you (should) do it right away.
另外，还有一些特殊的省略情况：
1. 所有格之后的名词如果是商店、工厂、住宅或是当地人比较熟悉的学校、医院、机关等时，该词往往可以省略。如：
At the doctor's, I met one of my old friends.
At the tailor's, I tried on several modern
dresses.
2. 在比较性的句子中，后一个数词或形容词修饰的与前面名词相同的名词往往省略。如：
A tall man is not always better than a short (man).
Two heads are better than one (head).
3. 动词不定式前的名词，若被序数词、最高级形容词或next，last等修饰时，该名词也通常省略。如：
Who is the next (student) to read the text?
He is always the first (man) to come and the last (man) to leave.
4. 对前面某种说法表示同意、肯定或加以强调时，常使用"So+主语+助动词"结构，以避免重复。如：
-It is sunny today.
-So it is. (=It's really sunny today.)
5. so常与think, guess, believe, suppose, expect, fear, be afraid, hope等连用构成省略句。如：
-I think it is going to rain.
-Yes, I think so. / I am afraid so.
6. not常与hope, think, guess, believe, expect, fear, be afraid, certainly, of course, perhaps等连用构成省略句。如：
-Do you suppose John is honest?
-No, I believe not.