动词不定式用法动词不定式没有人称和数的变化，在句中不能独立作谓语。
但动词不定式具有名词、形容词和副词特征，在句中可以作主语、宾语、宾语补足语、定语、表语和状语等多种成分。
另外，动词不定式具有动词特点，可以有自己的宾语和状语，组成动词不定式短语。
动词不定式的肯定形式是to＋do；其否定形式是not to＋do。
下面以动词不定式在句中的作用来予以详细说明。
1．作主语可以直接作主语。
如：To see is to believe．但在英语中，常用it作形式主语，真正的主语即动词不定式放在后面。
如：It's wrong to play tricks on other people．It's our duty to keep our environment clean and tidy．点击规律：动词不定式在句中作主语时，常放在It is ＋adj．（形容词）＋to do sth．或It is ＋n．（名词）＋to do sth．句型中，it仅作形式主语。
2．作宾语a．want，decide ，agree等动词后面跟并且只能跟不定式。
如：We agreed to start early．She wants to be a doctor．b．love，like ，begin，start，hate ，prefer等词后面可以接不定式。
点击规律：上述动词后面除接不定式外，还可以接动名词，意思无很大区别。
提示板：like doing指经常性动作，而like to do指一次性的动作。
如：I like swimming，but I don't like to swim now．我喜欢游泳，但我现在不想游。
c．stop，forget，remember，go on ，try等词或短语后面可以接不定式。
点击规律：上述动词后面接不定式和接动名词意思大不相同。
提示板：1）stop to do sth．：停止一件事，去做另一件事。
stop doing sth．：停止正在做的事。
例句：When the teacher came in，the students stopped talking；when he came out，the students stopped to talk．当老师走进来时，学生们停止说话；当老师走出去时，学生们又开始说话。
2）思考：forget，remember，go on，try等词或短语后面接不定式和动名词用法有何区别？d．在find／feel＋it＋adj．＋to do sth．句型中，it是形式宾语，真正的宾语是后面的动词不定式。
如：The man downstairs found it difficult to get to sleep．I feel it easy to recite the text．点击规律：某些动词或短语后面既可以接动词不定式作宾语，又可接动名词作宾语，二者用法上的区别可以通过造句子加以区分，如上面stop例句。
3．作宾语补足语a．tell，ask，want，order，teach，invite，warn，wish，help，get，wish，help等词后面常接不定式作宾补。
如：I tell him not to go there by bus ．Edison's mother taught him to read and write．b．let，make，have，see，hear，feel，watch，notice后面接不带to的不定式作宾补。
如：The boss makes them work 16 hours a day．I heard her sing in the next room．提示板：若变成被动语态，在上述结构中，不定式符号to要加上。
如：They are made to work 16 hours a day by the boss．She was heard to sing in the next room．4．作定语：放在被修饰的名词、代词后面例句：I have a lot of work to do．The doctor said he could do nothing to help the boy．点击规律：动词不定式若在句中作定语，常放在被修饰的名词、代词之后。
提示板：如果动词不定式和前面所修饰的词构成动宾关系，若动词是不及物动词，切记不要忘掉介词。
如：I have a small bedroom to live in．Have you got some pens to write with？5．表语：放在连系动词be后面例句：His wish is to become a scientist．The first important thing is to save the soldiers' lives．当务之急是抢救战士们的生命。
点击规律：动词不定式在句中作表语时，通常对连系动词前面的名词进行诠释说明。
6．作状语a．目的状语：放在go，come，use，live，in order等词后面。
如：I come to see you．He runs fast in order to get there in time．b．原因状语：放在sorry，glad，surprised，disappointed，excited等词后面。
如：I am glad to see you here．I am sorry to trouble you．c．作结果状语。
如：Some of the apples are hard to reach．The room is large enough to hold 1000 people．7．与what，who，whose，when，where，how等疑问词连用，作宾语、宾语补足语、主语等。
如：I don't know what to do next．（宾语）He taught us how to use the computer．（宾语补足语）It's still a question how to get there．（主语）【模拟试题】（答题时间：30分钟）一. 选择填空：1. He asked me ________ here earlier.A. comeB. to comeC. comingD. came2. Please tell him _______ on the wall.A. don’t drawB. to not drawC. not to drawD. not draw3. He wanted ________ a cup of tea.A. to haveB. havingC. haveD. had4. I’d like ________ a word with you.A. hadB. havingC. to haveD. have5. I came here _______ my uncle.A. sawB. to seeC. seeingD. to be seen6. The man refused （拒绝）________ back his words.A. to takeB. takingC. tookD. takes7. I can let you ________ one ticket.A. to haveB. haveC. havingD. had8. We often heard him _________ in his room.A. to singB. singsC. sangD. sing9. He was made ________ day and night.A. workB. workingC. to workD. worked10. He stopped ______ a look, but saw nothing.A. havingB. to haveC. haveD. had11. My father was too angry _________ a word.A. to sayB. not to sayC. to sayingD. didn’t say12. My brother was old enough ________ to school.A. wentB. goesC. goingD. to go13. It is time ________ him ________ supper.A. of, to haveB. for, to haveC. of, havingD. for, to has14. It’s very kind _______ you ______ me.A. of, to helpB. for, to helpC. of, helpD. of, helping15. It’s important _________ our classroom clean every day.A. keptB. to keepC. to giveD. keep16. Before liberation （解放）they had no chance _______ to school.A. wentB. goC. to goD. to be gone17. He said he had an important meeting ________.A. attendB. would attendC. attendingD. to attend18. Please give me a piece of paper ________.A. to writeB. to write onC. writingD. to write it19. I don’t know _______.A. what doB. what will doC. what to doD. do what20. Your radio needs ________.A. to be repairedB. to repairC. repairedD. to repairing21. My wish is ________ a teacher.A. becomingB. to becomeC. becomeD. became22. I want ________ him a letter now.A. to writeB. not writeC. writeD. wrote23. It took us three days _________ the trees.A. plantB. plantedC. to plantD. plants24. Why not ________ here _______ me?A. to come, to seeB. come, to seeC. came, seeingD. come, see25. He wishes me ______ my best _________ hard at English.A. to do, to workB. doing, workingC. to do, workingD. do, work26. Please tell me ________ her. I have something _______ her.A. where to find, tellingB. where to find, to tellC. where can find, to tellD. where finding, telling27. How happy they are ______ each other again!A. to seeB. seeC. sawD. being seen28. They decided （决心）_______ a letter ______ their thanks.A. to write, expressing（表达）B. writing, expressC. write, expressedD. to write, to express29. The officer ordered （命令）him _______ down _________ a rest.A. lying, haveB. to lie, to haveC. to lie, havingD. lie, had30. The headmaster called on （号召）us ______ hard for our country.A. to workB. workedC. workD. to working二. 根据上句意思完成下句，使两句意思相近或相同，每空一词。