不定式用法总结

动词不定式作表语，一是主语有不定式充当；二是主语由抽象名词充当。 To teach is to learn. My job is to help the patient. 【注意】如果在主语中（通常在主语从句或修饰主语的定语从句中）又 实意动词do时，作表语的动词不定式省略to。 All I want to do now (What I want to do now) is fill my stomach.
He was seen to break the window.
可后接动词不定式作宾补的动词有：advise, allow, ask, hear, order, see, tell, want, wish, expect ,watch等。 ①The doctor advised her not to eat too much sugar. ② I wish you to go to the meeting with me. ③The government calls on us to increase our production.
4．作宾语不足语


【注意】在感官动词（see, hear, feel, listen to , notice, watch, observe等）和使役动词（let, have， make ）后的补足语中，不定式 不带to。但这类句子变成被动语态时，必须带to。 I saw him play in the park. →He was seen to play in the park. The boss made those men work day and night. →Those men were made to work day and night.

I had nothing to do but watch TV.
② 当句子的谓语动词是can’t, can’t help, can’t choose 等结构时, but, except, besides后的不 定式to 也省略。 We can’t but admire his bravery. We can’t choose but wait。 She is such a lovely girl that I can’t help but love her.


I came here to see you . （目的）
We were very excited to see our football team won. （原因） Peter saved a girl’s life on his way to work and then hurried to his office, only to be told by the boss that he was fired because he was late again. (出乎预料的结果） To look at him, you would like him.（条件） To learn a foreign language well, you must spend a lot of time and effort on it .（目的）
注意:
but
作 “除了…以外” 解时, 若前面部分有
do, did, done时, but 之后接do sth. 反之, 后接
to do sth.
He
can do nothing but wait.
He
wanted nothing but to play in the park.
3．作表语
5．定语
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1、不定式与被修饰的名词往往构成逻辑上的关系。如名词 为不定式的逻辑主语，构成主谓关系； 若名词为逻辑宾语， 则构成动宾关系； He is not the first employee to arrive at the office this morning. There will not be enough space to stand in on the earth I have some books for you to read. 2、作定语的不定式与所修饰的名词之间是动宾关系， 不定 式动词又是不及物动词时，应在该动词上加上一个介词，如; He has a nice pen to write with. He is looking for a room to live in. He is said the best way to travel by is on foot.
but+不定式的用法 ①不定式在介词 but, except, besides, other than 后面 时, 如果这些介词之前有行为动词do (非助动词)的各 种形式时, 那么这些介词后面的不定式不带to,否定带 to。e.g.

She could do nothing but cry. What do you like to do besides swim? I have no choice but to wait. There was nothing for me to do other than wait until the meeting was over.
动词不定式的基本用法归纳
一、动词不定时的形式： 肯定式：to do sth 否定式：not to do sth. 被动式：to be done 一般被动否定式：not to be done 完成主动式：to have done 完成否定式： not to have done 完成被动式：to have been done 完成被动否定式： not to have been done
动词不定式的基本用法归纳
二、动词不定式的用法 1．作主语 A 动词不定式作主语，谓语动词用单数形式。如： To see is to believe.(Seeing is believing.)


My chief purpose is to point out the difficulties of the matter. Her wish is to become a doctor.
hope, demand, suggest等动词不能后接 动词不定式作宾补。 ①I hope my son will be back soon. ②She advises us to have a discussion about it. ③She suggests that we (should) have a discussion about it.
B 不定式或不定式短语作主语时，常用it作形式主语，构成“It is + 形容词(+for sb.)不定式”结构。 It is impossible for him to give up smoking.
2.作宾语




A．动词后直接不定式作宾语的动词有许多，如want, decide, intend, fail, wish, export, pretend, choose等等。 I mean to go there at once. B.不定式短语作宾语时，如果还带有宾语补足语，往往把不定式短语放 在宾补之后，而用it作形式宾语。句型为“主语+find (feel, think, believe, consider,etc) +it+形容词/名词+to do sth”。 I think it necessary to report the thing to the teacher. I find it interesting to work with him. C．动词不定式还可以用作介词宾语，但仅限于介词except和but（除 了）。 常用句型有： There is nothing to do but+动词原形 do nothing but+动词（除做….之外别无选择） can but+动词原形 （只能原形(“只有做……) have no choice but to do ，只得） cannot help/choose but+动词原形(不能不……）


作目的状语，还可以使用in
order (not )to
或so as(not) to。 ①The boy worked so hard in order to make up for the lost time. 结果状语还可以使用enough to, too…to…, so…as to, such… as to等结构。 ①He got up too late to miss the early bus. ②She was in such a hurry as not to notice me. 她如此匆忙，以致没有注意到我。
6.作状语
不定式作状语时，可表示目的，原因，结果或条件。 如; I’m very glad to hear the news. （原因) 不定式作目的状语时，常可与to, to order to, so as to 连用。 He got up early so as not to be late. 不定式可以跟在表语的形容词之后作状语。 The question is difficult to answer.。 有些不定式短语可以做独立成份，通常放在句首， 有时置于句中或句未，须用逗号的开。
believe, consider, count, declare, deny, feel, find, guess, imagine, judge, know, prove, realize, suppose, think等动词后可接 to be型不定式作宾补。 ①He declared himself to be a college student. 他自称是名大学生。 ②The police proved him to be a thief. 警察局证实他是小偷。
动词不定式作定语，应位于所修饰词语之后， 即：作后置定语。 ①Have you got anything to eat? (to eat修饰 anything，位于其后) 下列名词后常接动词不定式作定语：ability, attempt, chance, courage, decision, effort, failure, promise, way, wish等。 ①But she gave up the chance to go abroad. 由only, first, last, next以及序数词或形容词最 高级修饰的名词后，也常接不定式作定语。 ①Who was the last one to leave the classroom last night?