动词不定式的用法
动词不定式的形式：
动词不定式的用法
1.不定式作主语
⑴原则上，可用动词不定式直接作句子的主语，通常用it作句子的形式主语，而把不定式移到后面，形成“It + 谓语? + 动词不定式?”的句型。如：
To catch the 5：00 bus early in the morning is not a good idea.
It is not a good idea to catch the 5：00 bus early in the morning.
To learn a foreign language well takes painstaking efforts.
It takes painstaking efforts to learn a foreign language well.
⑵若要说明不定式的动作的执行者，可以在不定式前面加上“for + 名词或代词”结构，或是“of + 名词或代词”结构。
It is a great pleasure for me to talk with him. It is very kind of you to help me .
⑶可用于“of + 名词/代词 + 动词不定式”结构中作主语补足语的形容词是指那些可以表示人或事物的性质或品质的好坏的形容词。这些词如：careful， cruel， foolish， bold， brave， good， honest， kind， rude， polite， nice，stupid， selfish， silly， wicked， wise， thoughtful， wrong等。
2.不定式作宾语
不定式作宾语有两种情况：一是及物动词后直接跟带to的不定式，二是“动词+疑问词+带to的不定式”。
⑴“动词+带to的不定式”结构：常见的以不定式作宾语的动词有afford， appear， agree， ask， believe， decide， demand， desire， fail， hope， intend，learn， mean， offer， promise，refuse， wish等。如：I can‘t afford to buy a house.
⑵“动词+疑问代（副）词+不定式”结构：常见的这类动词有advise， decide， forget， know， learn， remember， see， tell， think， teach， wonder，discover， understand， guess， explain等。这类疑问代（副）词what， when， which， where， how， whether等（不包含why）。如：
She does not know how to go there. He will tell you how to deal with it.
⑶在不定式作宾语时，有时我们会使用it作形式宾语，而把不定式放到后面。如： They consider it inappropriate to have classes in the evening.
（4）可以作形容词的宾语。这一类形容词有glad, sorry, afraid, pleased, determined, willing, eager, anxious等。例如：
I”m determined to give up smoking.
He is willing to help us.
（5）在tell, advise, allow, forbid, learn, show, decide等词的后面常用“连接词+不定式”作宾语。例如：
We must decide whether to go or stay.
I don”t know how to get in touch with him.
3.不定式作表语
不定式作表语时，主语通常是一个名词，不定式短语或者从句。
The boss‘s plan is to start building the skyscraper immediately. To work means to earn a living. What you have to do is to push the button.
4.不定式作定语
不定式作定语相当于一个定语从句，它修饰以下几类名词：
⑴由动词派生或转化而来的名词，它们所对应的动词通常有不定式作宾语。这类名词主要有：attempt， claim， decision， plan， promise， intention， need，resolution，tendency， wish， failure， threat等。
Another attempt to climb the mountain will be made next month.
In his speech he expressed his determination to achieve the goal.
⑵由可能与不定式搭配的形容词派生出来的名词。这类名词主要有：anxiety， patience， ability， willingness， ambition等。
Her eagerness to learn a foreign language obvious.
⑶不定式作定语还可用来修饰代词something， anything， everything， nothing.不定式做后置定语。
Do you have anything to send? 你有什么东西要寄吗？（不定式to send的动作执行者是you）
Do you have anything to be sent? 你有什么要（我或别人）寄的东西吗？不定式to be sent的动作执行者是已被省略的me或someone else）
She has everything to lose and nothing to gain.
⑷由only， last， next， 序数词或形容词最高级修饰的名词后常用不定式作定语。 Jim is the only student to answer the question correctly in his class.
You are the last to undertake the blood test.
⑸不定式常作为定语修饰there be结构的真实主语。在there be结构中，用来修饰主语的不定式有时用主动形式，有时用被动形式。当说话人考虑的是必须有人完成某件事时，不定式用主动形式。如果说话人强调的是事情本身必须被完成时，不定式则用被动形式。例如：
There is a lot of work to do.（Somebody has to do the work.）
There is a lot of work to be done.（The work has to be done.）
⑹ 有些抽象名词。主要有：reason， right， time， effort， chance， way等。如： the time to go to school， the way to get to the clinic， the chance to win the game.
(7)如果不定式中的动词是不及物动词,则不定式中要有介词. I have something to say. He has a lot of homework to do . He is looking for a room to live in . There is nothing to worry about.
不定式所修饰的名词或代词是不定式动作的地点工具等，即使是及物动词，不定式后面仍须有相应的介词。
Please give me a pen to write with.
不定式所修饰的名词如果是time, place或way，不定式后面的介词习惯上要省去。
He had no money and no place to live. 他没钱没地方住。
(8)不定式作定语时，应放在被修饰词的后面，而且放在其他后置定语之后。不定式做定语与所修饰的词之间有三种关系：
1)动宾关系 I have a lot of work to do.我有很多工作要做。
2)主谓关系 He is always the first to come.他总是第一个来。
3)同位关系 We all have a chance to go to college. 我们都有上大学的机会。
5.不定式作状语 不定式作状语相当于一个状语从句，表示形为的目的、结果或原因。 ⑴表示目的。在这种情况下，不定式的逻辑主语通常也是全句的主语。 He stayed there to see what would happen.
在强调不定式目的状语时，不定式前可加in order， so as等。如：
She asked me to drive her to the airport in order to catch the 5：00 plane.
He moved the TV set to the meeting-room so as to let everyone watch it.
⑵用so??as to??， such （??） as to??， enough to??， too??to， only to等表示结果，如：
Have you got enough room to seat all of us？
She is too weak to join us in the outing.
⑶将不定式移到句首表示条件，如：
To hear the teacher better， you have to sit in the front. = If you are to hear the teacher better，??
⑷与形容词连用时，大多表示原因。这些形容词主要有：happy， kind， surprised， frightened， angry， shocked， glad， delighted， grieved，disappointed等。 They were surprised to be informed of the news. I‘m glad to hear this.
6、独立结构
To tell the truth, I don’t agree with you.
? to be frank,
? to be honest,
? to tell the truth
7、关于小品词to
(1).不定式中的动词上文已出现过,下文要省略该动词.
eg: Would you like to go with me ? I’d like to .
(2). 不定式是to be 结构, be 不可省.
eg: Would you like to be a teacher? I’d like to be.
? 不定式与疑问词who,which, when, how, what 等连用，在句中起名词作用，可充当主语、表语、宾语等。
He didn’t know what to say.他不知道说什么。(宾语)
How to solve the problem is very important.如何解决这个问题很重要。(主语) My question is when to start.我的问题是什么时候开始。(表语)
? 在与why连用时，只用于why或why not开头的简短疑问句中，后面紧跟的动词不定式不带to。
Why not have a rest?
8、固定句型:
? had better/had best + (not) do sth.最好（不）做某事
? Why (not) do sth.?
? ?prefer to do/prefer doing
? ?prefer + n./doing A +to + n./doing B
? ?prefer + to do A rather than (to) do B
? ?would rather (not) do sth.
? ?would rather do A than (do) B
? ?would rather + 句子（过去式） （虚拟语气） 要做??
动词不定式的时态和语态
一般式 to do to be done
完成式 to have done to have been done
进行式 to be doing
完成进行式 to have been doing
1.如果不定式所表示的动作与主要谓语动词所表示的动作同时（或几乎同时）发生或发生在主要谓语之后，通常用不定式的一般形式。如：
I saw him go out.
I‘m glad to see you.
2.如果不定式所表示的动作发生在主要谓语动词或特定的时间之前，不定式就要用完成式。如： I intended to have telephoned you， but I forgot to.
I should like to have bought a dictionary.
3.不定式进行式表示主要谓语动词所表示的动作发生时，不定式所表示的动作正在发生。如： I am glad to be talking with you. She pretended to be listening attentively.
4.不定式完成进行时表示的是一个开始于过去某一时刻但一直延续到谓语动词发生的那一时刻的动作。如：
He was thought to have been working on the project for two years.
5.不定式的被动语态
当不定式的逻辑主语是动作的承受者时，这个不定式要用被动式，包括它的各种时态在内。如： She doesn‘t like to be treated as a guest.
她不喜欢被当作客人对待。
They want their TV set to be fixed right now.
他们想把电视机马上修好。
There are a lot of things to be done.
有许多事要做。
This is the text to be read next time.
下次就读这篇课文。
注意：有些习惯用法中，只能用主动语态。如：
The house is to let.
这房子要出租。
A lot of work still remains to do.
许多工作有待去做。 (1).They pretended not to see us.(一般式表示与谓语的动作同时/几乎/发生在它之后.) (2). He pretended to be sleeping. (在谓语动词发生的同时,不定式的动作也正在进行) (3).She pretended to have known it before.(完成式表示动作发生在谓语动作之前)
(4).We’re happy to have been working with you.(完成进行式表示谓语动作发生之前,不定式的动作一直在进行而且可能之后也继续)
不带to 的不定式
1.表示感觉的动词
五看see，notice，watch，observe，look at 三使have，let，make 二听hear，listen to 一感觉feel
He noticed the man enter the room. 他注意到有人进屋了。
They observed her do the experiment. 他们观察她做实验了。
2.help后的不定式可以带to也可以不带to.
Can you help me （to） clean up after the meal？ 饭后你能帮我洗碗吗？
3.有些类似于情态动词的词语（如rather than， had better， would rather， might as well等）之后，不定式不带to.如：
We might as well go without him. 我们可以不让他跟去。
You‘d better go now. 你最好现在走。
4. 不定式用在介词but, except, besides后时,如果这些介词前有行为动词do的各种形式,那么介词后的不定式不带to,相反则带to.
(1). She could do nothing but cry.
(2). I have no choice but to go.
(3).What do you like to do besides sleep