初二年级英语动词不定式复习动词不定式构成：肯定式：不定式符号to+动词原形否定式：not to+动词原形一、用作主语1、把不定式置于句首。
To get there by bike will take us half an hour.2、用it作形式主语，把真正的主语不定式置于句后，常用于下列句式中。
①It＋be＋名词＋to doIt's our duty to take good care of the old.②It takes sb + some time +to doHow long did it take you to finish the work?③It＋be＋形容词＋for sb＋to do 逻辑主语如：difficult, easy, hard, important, impossible, necessary 等；It is difficult for us to finish writing the composition a quarter of an hour.④It＋be＋形容词＋of sb＋to do常用careless, clever, good, foolish, honest, kind, lazy, nice, right, silly, stupid, wise等表示赞扬或批评的词，强调对人的评价。
“It is stupid of you to write down everything”，the teacher says.⑤It seems(appears)＋形容词＋to doIt seemed impossible to save money.3、带疑问词的不定式短语作主语How to solve the problem is hard for him.二、用作表语动词不定式作表语，通常放在连系动词（主要是be动词）后。
1.The best way to improve your English is to join an English club.2.The first thing is to greet the teacher.注意：不定式作表语表示具体动作或将来动作；动名词作表语表示抽象的一般行为。
Our work is serving the people.三、用作宾语1.可以接带to的动词不定式作宾语的动词主要有：要求、选择、同意(ask to do, choose to do, , agree to do, )，期望、决定、学习(expect to do , hope to do, , decide to do, ,learn to do) 宁可、假装、知道(prefer to do, pretend to do, know to do )希望、想要、愿意(wish to do , want to do, would like / love to do)。
如：1)We decided to talk to some students about why they go there.2)He prefers to eat white bread and rice.3)I’d love to visit Mexico2.动词decide, know, learn, show, teach, tell...，介词结构on...，可用疑问词带to的不定式短语作宾语，但why后面的不定式不带to。
如：1)Could you please tell me where to park my car?2)It gives advice on what to do in lots of different situations.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:...feel / find / make / it+adj. / n.+to do...。
如：I find it difficult to remember everything.4.既可接动词不定式又可接ving形式作宾语，意思差别不太大的动词有begin, start, like, love等。
一般说来，动词不定式表一次、数次的具体动作、将来动作或动作的全过程，v-ing形式表习惯性的连续动作。
但是这种区别并不很严格，特别是美国英语，即使是习惯性的动作也可以用动词不定式。
如：1)Then I started to watch English-language TV.2)I’m beginning to understand my Chinese roots, and who I am.begin用了进行时态，后面只接不定式作宾语，表示事情刚开始，还要继续下去。
3)I like to eat vegetables.感知动词like, love, know等一般不用进行时态。
5.后接动词不定式或v-ing形式作宾语，意思差别较大的动词有forget, remember等。
后接不定式作宾语，表动作尚未发生；后接v-ing形式作宾语，表动作已经发生。
stop to do停下来做另外一件事，to do是目的状语；stop doing停止做、不做当前这件事，doing是宾语。
try to do尽力做，try doing试试看；go on to do接着做另外的事，go on doing 继续做原来的事。
如：1)When I left home, I had forgotten to bring it with me.2)I stopped using them last year.总结：“及物动词+不定式一般形式：及物动词+疑问词+不定式：四、用作定语1)I have so many chores to do today.2) Do you have anything to say on the question?3) Would you please give me some paper to write on?2.动词不定式所修饰的名词是place, time, way等时，不定式与这些名词呈现出动状关系或同位关系。
1)He needs time to do homework2)Is that a good place to hang out？3)You want to know the best way to get around the city.3.在“there be...”句型里，句子的主语是动词不定式动作的对象，常用主动式。
如：1)There’s just so much to see and do here.2)... but there are still many things to do there.1、记住下面的一些结构：2、在这种情况下,如果不定式动词是不及物动词,则后面必须加介词。
They could not find a place to live in. (他们找不到住的地方)Please give me a chair to sit on. (请给我一张椅子坐坐)He has got a writing brush to write with. (他找到了写字的毛笔)五、用作补语1.要求、允许、提议(ask, allow, permit, advise)，期望、邀请、鼓励(expect, suppose, invite, encourage)，教导、告诉、想要(teach, tell, want)，等待、希望、愿意(wait for, wish, would like / love)。
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，多数动词是感官动词和使役动词，包括:一“感觉”feel；二“听”：hear, listen to；三“让”：have, let, make；四“看”：look at, observe, see, watch；五“注意”：notice。
I saw him dance.=He was seen to dance.The boss made them work the whole night.=They were made to work the whole night.3.help后接动词不定式作补语，to可带可不带。
一般说来，带to表间接帮助，不带to表直接帮助。
在被动语态句里，或者用不定式的否定式作补语时要带to。
如：4.be said, be sure, happen, seem等后面可以接带to的动词不定式作主语的补语。
如：1)He doesn’t seem to have many friends.2)Be sure not to miss them if they come to a city near you. 总结：注意：hear / see / feel / watch之后的宾补用不定式与现在分词时,含义不同,试比较：I heard her crying when I walked past.(我路过时听到她正在哭)(指当时瞬间的情况)I sat near her and heard her sing the new song.(我坐在她附近听她唱新歌)(指整个过程)六、动词不定式作状语1.目的状语，to do置于句首或句末，置于句首时常表示强调。
A group of young people got together to discuss this question.2.原因状语，多见于“sb.+be+adj.+to do...”结构句中。
I'm glad to see you .3.结果状语，多见于“too...to”(太…以致不能…)，“enough to...”结构句中。
He is too excited to speak.七、带疑问词的不定式短语疑问代词what to do, which to do, who to do或疑问副词how to do, when to do, where to do, why do等。
这种结构起名词的作用，在句子里用作宾语、主语、表语等，或者单独使用。
要注意的是：why后面的不定式不带to。
如：1.用作句子的成分。
1)I don’t know what to do. = I don’t know how to do it . (作宾语)2)Where to go is not decided yet. (作主语)2.单独使用时相当于一个特殊疑问句。