不定式在句子中可以作主语.宾语.宾补.表语.定语和状语：
1.不定式作主语
To learn a foreign language is not easy. 学外语不容易。
Is it necessary to complete the design before National Day? (it 为形式主语 ) 有必要在国庆节之前完成这个设计吗？
如果要说明不定式表示的动作是谁做的,可以在不定式前加for引起的短语,即for +名词/代词宾格+不定式。
It is good for us to take part in physical labour 参加体力劳动对我们有益
某些表示人的品行的形容词(如kind, good, nice, wrong, careless, wise, foolish, polite, clever, right,
unwise, stupid, thoughtful, rude, silly, impolite等)作表语时不定式前常可用of引起的短语,既be+形容词+of+ 名词/代词的宾格+不定式.
It is stupid of her to make such a mistake. 她真蠢,犯这样的错误
2. 不定式作宾语
I forgot to turn the oven on. 我忘记打开炉子。
有些及物动词用不定式作宾语，结构为动词+不定式。
afford aim agree arrange ask decide promise care choose demand desire determine expect hate hope fail help learn
long mean manage offer plan pretend refuse intend bother tend
3.不定式作宾语补足语
不定式可以和名称或代词构成复合结构,作动词的宾语,不定式作宾语补足语
We advised him to have a good rest 常带不定式作宾语补足语的动词有 ask, tell, invite, force,
advise,get,beg,allow,help,want,wish,like,order,expect,prefer,encourage,hate,warn,permit等.但在make, let, have, see, hear, watch, notice, feel, observe, listen to, look at 等动词后的复合宾语中,不定式不带to. 在help后不定式可以带to,也可以不带to The boss made the workers work day and night.老板迫使工人们日夜干活 Will you help me (to) plant this tree, please? 请您帮我种这棵树好吗？
4. 不定式作定语
He has a lot of questions to ask. 他有许多问题要问。
不定式作定语时,须放在被修饰的名词或代词之后.不定式常和它修饰的词有动宾关系.如果这个不定式是不及物的,它后面应有必要的介词
I use a pen to write with.
5. 不定式作表语
Disney’s greatest wish was to be a famous artist. 迪斯尼最大的愿望就是成为一个著名的艺术家。
6.不定式作状语
不定式作状语可以修饰动词,表示目的,结果,或原因
To catch the first bus, I have to get up early. (目的)
She went aboard never to return. (结果)
I was surprised to see him there.(原因)
不定式的否定形式
否定式的否定形式是在不定式符号to前加not 构成
He decided not to go home.
疑问词+不定式结构
疑问词who, which, what, when, where, how, whether等后接不定式,构成不定式短语,在句中作主语.表语.宾语等。
When to start has not been decided.（主语）
I don’t know what to choose.（宾语）
The question is how to put the plan into practice.（表语）
动词不定式省略to的情况
1. 在助动词或情态动词后面
May I ask you a question? 我可以问你一个问题吗?
2. 在 make, let, see, watch, hear, notice, feel, have, listen to , look at等动词后(作宾语补足语)
Let me hear you play the piano. 让我听你演奏钢琴吧。
3. 在why引起的某些问句中
Why turn off the gas? 为什么不再试一下？
4. 在had better, would rather, would rather…than, would sooner, would sooner…than, cannot but, do nothing but 等结构后面
He can’t but agree (他不得不同意)
He would rather /sooner die than surrender(他宁死不屈)
My mother could do nothing but wait for the doctor to arrive (我妈妈没办法,只好等医生来)
5. 在 “Will you please + 动词不定式” 一类表示邀请或命令的句型中
Will you please bring me some chicken? 请给我带点鸡肉来好吗?
6. 在 “Why…” 或 “Why not…” 一类表示建议的句型中
Why not join us? (= Why won’t you join us?) 为什么不加入到我们中来吗?
7. 在介词except, but之后,如果其前有动词do的某种形式,不定式一般不带to,反之则带to
There is nothing to do except wait till it stops raining (没办法,只好等雨停了) There is no choice but to wait till it stops raining (没办法,只好等雨停了)
8. 当作宾语的不定式再次出现时,为了避免重复,不定式往往省略,只保留不定式符号to.常出现在下列动词后:want, wish, like, love, hope, plan, try ,hate 等 You don’t have to eat if you don’t want to.如果你不想吃,就不必吃了
--Have you listened to the music? 你听了那首曲子了吗?
--No, but I plan to 没有,但我打算听
I.句型转换
1. It is impossible that a child can lift such a heavy box.
It is impossible _______________________such a heavy box.
2. It happened that you had known each other before.
You happened ____________________each other before.
3. The progress which will be made soon is of great importance.
The progress _________________________ is of great importance.
4. The boss made the workers work all night.
The workers were ______________all night.
5. When we should hold the meeting is still to be discussed.
When _________________ the meeting is still to be discussed.
6. It seemed they were writing something for somebody.
They seemed _______________________something for somebody.
7. I find that it is difficult to speak English well.
I find ____________________to speak English well.
8. Jane doesn’t know how she can improve her Chinese.
Jane doesn’t know__________________ improve her Chinese.
9. The girl got up earlier so that she might not be late again.
The girl got up earlier_______________________ be late again.
10. We found the lesson was difficult to understand.
We found the lesson _______________________.
II.单项选择
1. I’m going to the supermarket this afternoon. Do you have anything____?
A. to be buying B. to buy C. for buying D. bought
2. She will tell us why she feels so strongly that each of us has a role______ in making the earth a better place to live.
A. to have played B. to play C. to be played D. to be playing
3. Having a trip abroad is certainly good for the old couple , but it remains _______whether they will enjoy it.
A to see B. to be seen C. seeing D. seen
4. It is said that in Australia there is more land than the government knows______.
A. it what to do with B. what to do it with
C. what to do with it D. to do what with it
5. ---- How do deal with the disagreement between the company and the customers? ----The key ______the problem is to meet the demand______ by the customers.
A. to solving; making B. to solving; made
C. to solve; making D. to solve ; made
6. In order to gain a bigger share in the international market , many state-run companies are striving ______ their product more competitive.
A. to make B. making C. to have made D. having made
7. In some parts of London, missing a bus means _____ for another hour.
A. waiting B. to wait C. wait D. to be waiting
8. In order to make our city green, _______.
A. it is necessary to have planted more tree B. many more trees need to plant
C. our city needs more tree D. we must plant more trees
9. With a lot of difficult problems _______,the newly-elected president is having a hard time.
A. settled B. settling C. to settle D. being settled
10. _____ you the truth, I didn’t want to tell you about it.
A. To tell B. Telling C. To be told D. Told
11. Let your mother know all the truth. She appears ______ everything.
A. to tell B. to be told C. to be telling D. to have been told
12._______late in the afternoon, Bob turned off the alarm.
A. To sleep B. Sleeping C. Sleep D. Having