为了避免重复，省略句子中的一个或几个成分，这种语法现象称为省略。不定式的省略一般有三种常见形式： 省略动词原形而保留符号to 、省略不定式符号to和省略整个带to不定式。
一、省略动词原形而保留符号to
动词原形的省略是指前面出现过的动词在下文再次出现时，可以单纯使用不定式符号to即：只省去动词，而保留符号“to ”。如：
. Don’t stop unless you have to (stop ).
You may bring the dictionary with you if you want to (bring it ).
---Will you go with me ?
---Well, I’d like to ( go with you ).
---Have you ever been to the seaside ?
---No, we can’t afford to ( go to the seaside).
就不定式在句中的所起不同作用这一角度来看，在语言意义十分清楚和语境非常明确的情况下，动词原形在以下几种情况下省略：
1． 动词不定式在 care, want, hope, wish , expect, prefer, refuse, mean, try , promise, like , love（尤其在 would like, would love, want等之后）等动词后作宾语时， 常常可以省略动词原形。如：
----Are you interested in going to university ?
----Yes, I would like to( go to university ).
2. 动词不定式在ask, warn, tell , advise, force, wish, expect, allow, permit 等动词后作宾语补足语或主语补足语时， 常常可以省略动词原形。如：
Don’t touch anything unless your teacher tells you to( touch them ).
As it is very hot, she wants to go swimming in the lake, but her mother doesn’t allow her to( go swimming ).
3. 动词不定式在happy, glad, eager, anxious, willing, ready等形容词后作状语时，动词原形可以省略。 95年NMET 第30题就是这种类型。如：
---Will you join us in the game ?
---Thank you. I’d be happy to (join in the game).
4. 动词不定式在与 be able to, be going to, have to, ought to, used to , mean to , try to, plan to等构成复合谓语时，不定式结构可以省略动词原形。97年NMET 第22题就是个例子。如：
We don’t go skating in winter as we used to (skate ).
---Do I have to go with them to swim ?
---You don’t have to (go ) if you have something important to do.
二、省略不定式符号to
1. 在语言意义十分清楚和语境非常明确的情况下，为避免重复，常出现不定式符号to被省略的情况, 98年NMET第10 题就是一例。值得注意的是，like 和 want 之后在一般情况下，to是不能省略的，但在从句中（如在when, if, as 之后），to 常常省略。如：
---Try to be back by 12 o’clock, will you ?
---Ok, I’ll try( to ).
---Shall I go to play ?
---If you like (to ) , you can go now.
2 .当两个或多个带to 的不定式由并列连词and 或 or 连接在一起时，第二个（及其后的）不定式符号常省略。如：
I want him to write these sentences down and (to ) translate them into Chinese.
I asked the students to read over this article carefully and( to ) write down the important points or ( to )put forward questions if there are any.
但： 当两个或多个带to 的不定式并列使用时，若有对比关系，那么每个前面就得加to。如：
He hasn’t decided whether to go home or to stay at school during the vacation.
To try and fail is better than not to try at all .
三、省略整个带to不定式
在语句结构相对独立、语意非常清楚的情况下，整个带to的不定式可以省略。如：
----Would you go with me this evening ?
----Sorry, I don’t have time ( to go ).
She should attend the English party, but she was shy ( to do so ) .
EXERCISES
1.You had better ______ your hair cut.
A. had B. have C to get D to have
2 We ______ put the meeting off for a week.
A can as well B. will as well C. shall as well D . may as well
3 He ______ live in the country than in the city.
A prefers Blikes to C had better D. would rather
4 The boy told his father that he would rather ______ an astronaut.
A. become B. to become C becoming D became
5 Paul doesn't have to be made ___. He always works hard.
A. learn B. to learn C. learned D. learning
6 --- I usually go there by train.
---- Why not ___ by boat for a change?
A. to try going B. trying to go C. to try and go D. try going
7 He wants to do nothing but ＿＿out.
Ａ to go Ｂ go Ｃ going Ｄgoes
8 He wants to believe anything but___ the medicine.
A to take B take C take D takes
9 Compared with women. men always prefer ____ at home rather than ____ so much time shopping .
A to finish ,to spend B to finish ,spend C finish ,spend D finish ,to spend
ANSWERS 1 A , 2 D ,3 D , 4 A ,5 B ,6 D , 7 B ,8 C ,9 B.
