英语动词不定式用法总结
动词不定式用法总结
动词不定式在句中可充当主语、表语、宾语、宾补、定语和状语等。
一、作主语
动词不定式作主语可位于句首。例如：
To learn a skill is very important for everyone.
It is very important（for everyone）to learn a skill.
也可使用it作形式主语，而将其置于句末。例如：
It is necessary （for young students）to learn a foreign language.
动词不定式作主语的常用句型有：
1. It is＋adj./ n. (＋for sb.／sth.) ＋to do sth.
用于此句型的形容词有：easy, hard, difficult, possible, important, impossible, necessary, good, bad, exciting, interesting, surprising等。例如：
It is interesting to play this game.
It is necessary for you to change your job.
It was impossible for them to complete the task in such a short time.
考例1：Is ____ possible to fly to the moon in a spaceship? (88 MET)
A. now
B. man
C. that
D. it
It is possible to fly to the moon in a spaceship.
用于此句型的名词有：pity, shame, pleasure, one’s duty, one’s job, fun, joy, good manners, bad manners等。例如：
What a pity it is for you to have missed such a wonderful film.
It is good manners for the young to give their seats to the old.
2. It is＋adj.＋of sb.＋to do sth.
该句型中只能使用描述某人的品德、特征的形容词，如：kind, nice, wise, silly, polite, impolite, friendly, foolish, clever等。例如：
How rude it was of the boy to jump the queue!
It is friendly of the family to try to make me feel at home in their house.
How silly it was of you to give up such a good chance！
3. It takes sb.＋some time＋to do sth.
该句型意为“做某事花费某人多长时间”。例如：
It took us half an hour to ride to the town by bike.
二、作表语
动词不定式作表语常用于以下结构：My wish/ job/ aim/ goal is…及The next step/ measure is …等。例如：
Your job is to type the papers in the office.
The next measure is to stop the river from being polluted.
三、作宾语
常见的只能使用动词不定式作宾语的动词有：agree, choose, decide, hope, fail, wish, refuse, expect, manage, plan, intend, pretend, promise, offer, afford, demand, arrange等。例如：They decided to build a highway between these two cities.
She offered to help me when I was in trouble.
believe, think, consider, feel, make等动词可用于“动词+ it +adj. / n+to do sth.”句型，其中使用it 作形式宾语，而将真正的宾语动词不定式置于句末。例如：
I think it necessary for us to have a good rest after the long work.
She felt it her duty to help the old woman.
四、作宾补
可后接动词不定式作宾补的动词有：advise, allow, ask, hear, order, see, tell, want, wish, watch等。例如：
The doctor advised her no to eat too much sugar.
I wish you to go to the meeting with me.
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。例如：
He declared himself to be a college student. 他自称是名大学生。
The police proved him to be a thief. 警察局证实他是小偷。
hope, demand, suggest等动词不能后接动词不定式作宾补。例如：
【误】I hope my son to be back soon.
【正】I hope my son will be back soon.
【误】She suggests us to have a discussion about it.
【正】She advises us to have a discussion about it.
【正】She suggests that we (should) have a discussion about it.
在主动结构中，下列动词后作宾补的动词不定式应省略to：“五看”(see, watch, notice, observe, look at)“三使”(make, let, have)“两听”(hear, listen to)“一感觉”(feel)。例如：
Who made him work all night long?
但是，改为被动结构后，应补出省略的to。例如：
He was seen to break the window.
五、作定语
动词不定式作定语，应位于所修饰词语之后，即：作后置定语。例如：
Have 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。例如：
But 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。例如：
Who was the last one to leave the classroom last night?
六、作状语
动词不定式作状语，可表示目的、原因、结果或条件。例如：
We went there to see our grandparents.（目的）
I am very sorry to hear that.（原因）
She hurried home only to find her father dead.（结果）
To look at the picture, you would like it.（条件）
作目的状语，还可以使用in order to或so as to。例如：
The 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。例如：
He got up too late to miss the early bus.
She was in such a hurry as not to notice me. 她如此匆忙，以致没有注意到我。
状语是用于说明地点、时间、原因、目的、结果、条件、方向、程度、方式和伴随状况等的一种句法成份。状语一般由副词、介词短语、分词和分词短语、不定式或相当于副词的词或短语来担当。其位置一般放在句末，但也可放在句首或句中。
1. 副词是一种用来修饰动词，形容词，副词或全句的词，说明时间，地点，程度，方式等概念。
He speaks English very well. 他英语说得非常好. （very是程度副词，用来修饰well。very well是修饰speak的程度状语）
2.介词短语
The boy was praised for his bravery. 那个男孩因为他的勇敢受到了表扬。（for his bravery在句中作原因状语）
3.从句作状语
If I am not busy tomorrow, I will play football with you. 如果我明天不忙，我将和你一起踢足球。（If
I am not busy tomorrow在句中作条件状语）
4. 不定式在句子中可以作目的状语。
I come specially to see you. 我专门来看你. （to see you在句中充当目的状语）
5.分词作状语
Having had a quarrel with his wife, he left home in a bad temper。和他妻子吵架后，他生气地地离家出走了。（having had a quarrel在句中作时间状语）
Reminded not to miss the flight at 15:20, the manager left for the airport in a hurry. （reminded not to miss the flight at 15:20在句中作时间状语）