英语to什么时候用不定式（英语中不定式todo）

非谓语是英语学习的重点也是难点，很多同学对这个语法知识一直是处于比较懵的状态。其实只要掌握非谓语所充当成分的用法就可以运用自如了。

非谓语，顾名思义就是不做谓语的动词的变化形式，即to do ，doing，done。除了谓语，句子成分中还有主语、宾语、表语、宾语补足语、定语和状语。

下面看看不定式(to do)充当这6种成分的用法：

一、不定式作主语

1.To see is to believe. （这种情况不常用）

2. It is important to learn English well.

It 是形式主语，真正的主语是 to learn English well. 这种用法是常用的而且是考点！考点！考点！

二、不定式作表语: 常说明主语的内容、性质和特征或表动作将要发生。

1. My job is to keep the children safe.

2.My task is to type the article.

三、不定式做宾语

1. He prefers to eat white bread and rice.
2. He wants to play football.

3.动词feel, find, make, think等后面，可以用it作形式宾语代替真正的宾语——动词不定式，句子结构是...feel / find / make / ... it adj. / n. to do...。

如：

I find it difficult to remember everything.

常接动词不定式作宾语的动词有：（需要记住！！！）

agree, afford, appear, ask, attempt；

care, choose, claim；

dare,decide,demand,deserve,determine；

expect, fail, get, guarantee；

hate, hesitate, hope, hurry；

intend, learn, manage, offer,

plan, prepare, pretend, promise；

refuse, seem, tend, threaten；

want, wish 等

四、不定式做宾语补足语

1. I'd invite her to have dinner at my house.

2 . We should allow the children to choose their own clothes.

Note 1: 带to的动词不定式作宾语补足语的动词主要有：要求允许提议(ask, allow, advise)，期望邀请鼓励(expect, invite, encourage)，教导告诉想要(teach, tell, want)，等待希望愿意(wait for, wish, would like / love)。

Note 2:动词不定式作补语，在主动语态句里不带to，被动语态句里带to时多数动词是感官动词和使役动词，包括四“看”：look at, observe, see, watch，三“让”：have, let, make，二“听”：hear, listen to，一“感觉”：feel，一“注意”：notice。

如、1. I made him do his work.

2.He was made to do his work (by me).

变成被动，被省略的to 要还原。

Note 3: 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.

如：1. She could do nothing but cry.

2. I have no choice but to go.

五、不定式做后置定语：只能用不定式做定语的情况很多，这里只列出常用和常考的4点

1. 当修饰的名词是抽象名词（看得见摸得着的名词是具体名词，如钢笔。看不见摸不着的词是抽象名词。），如：ability、 ambition、 attempt、 chance、 courage 、desire 、decision 、effort、 failure 、moment 、promise、 right 、time、 wish …（一些表示企图、努力、愿望、打算、能力等意义的名词）

He made a promise to come here on time tomorrow.

2.当修饰的名词前有the only, the next, the best, the first, the last, 以及由序数词或形容 词最高级修饰的名词常常用不定式作定语。

He was the first one to think of the idea.

You are the only person to be late.

The manager is the last to come to the meeting.

3.当修饰的词为 something, nothing, anything 等不定代词时。

Do you have anything to say?

There is nothing to worry about.

4.当定语表示未来的还没做的动作时。

The letter to be written is to my father.

The matter to be discussed is important.

六、用作状语

1.目的状语，置于句首或句末，置于句首时常表示强调。如：

1) To catch the early bus, she got up very early.

2)A group of young people got together to discuss this question.

3)She came to this city to visit her daughter.

2.原因状语，多见于“sb. be adj. to do...”结构句中。如：

I am very lucky to have him.

3.结果状语，多见于“too...to”，“enough to...”结构句中。如：

1) I’m too tired to do it well.

2)The room is big enough for three people to live in.

不定式2种独立用法

一、独立结构：

to be frank,

to be honest,

to tell the truth

这三个词组是同义词，意思是“说实话”、“老实说”或“坦率地说”

To tell the truth, I am not happy at the moment.

二、与疑问词连用：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.(宾语)

How to solve the problem is very important.(主语)

My question is when to start. (表语)

练一练吧

单选：

1. This company was the first ____ portable radios as well as cassette tape recorders in the world.

A. producing B. to produce C. having produced D. produced

2. The purpose of new technology is to make life easier, ____it more difficult.

A .not making B. not make C .not to make D. nor to make

3. Helen had to shout ______above the sound of the music .

A .making herself hear B. to make herself hear

C. making herself heard D .to make herself heard

4. I don’t know whether you happen_______ ,but I am going to study in the U.S.A this September.

A .to be heard. B. to be bearing C .to hear D .to have heard

5. The news reporters hurried to the airport, only ______the film stars had left.

A .to tell B .to be told C .telling D .told

6. You were silly not _______your car.

A. to lock B. to have locked C. locking D. having locked

7. The teacher asked us ______so much noise.

A .don’t make B. not make C. not making D .not to make

8. An army spokesman stressed that all the soldiers had been ordered _____clear warnings before firing any shots.

A .to issue B. being issued C. to have issued D. to be issued

9. I’d rather have a room of my own, however small it is, than_______ a room with someone else.

A. to share B. to have shared C. share D. sharing

10. The bank is reported in the local newspaper_________ in broad daylight yesterday.

A. robbed B. to have been robbed C. being robbed D. having been robbed

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