动词不定式,To do that sort of thing is foolish。,I want to see you this evening.,All you have to do is to finish it quickly.,We found a house to live in.,She came here to study English.,I warned the patient not to drink cold water after the operation.,主语,宾语,表语,定语,状语,宾补,不定式或不定式短语可起名词，形容词和副词的作用，在句中做主语，宾语，表语，定语，状语和宾语补足语。 一，不定式在句中的作用： 1、主语：不定式做主语时，可以直接放在谓语动词之前。 eg: To make a new dress takes her a lot of time.Not to get there in time is your fault. 注：常用it做形式主语，将to do放在位于之后，使句子保持平衡。,句型1：It + 谓语 + to do eg: It takes us an hour to get there by bus. 句型2：Its + n. + to do eg: Its our duty to help the poor. 句型3：It is adj. for/of sb. to do sth. 注：for/of sb to do sth 为不定式复合结构。1) of引起的复合结构只能做主语。 eg: Its very kind of you to help me.,2) for引起的复合结构在句中可做主语，宾语，表语，定语，状语等。 eg: Another method is for them to leave at once. (表语)Wed better find some work for the children to do. (定语)He put the paper on desk for you to read. (状语)What he told her made it impossible for him to go on her work. (宾语)Its common for leaves to fall from the trees in autumn. (主语),2、做表语：主语+系动词+不定式 1). 其主语多为抽象名词(wish, need) eg: My wish is to be a scientist.The main thing is to keep our room clean. 2). 不定式to blame做表语,主动表被动. eg: He is to blame. 3). be to do可构成将来时态,表 “准备/打算/计划/需要”; be是助动词，无词义,其主语为具体名词(人/事物); to be可用be going to或will/shall代替,此时不定式是谓语的一部分,而不是表语. eg: She is to return next week.He was about to leave when it started to rain.,3. 做定语: 不定式做定语总是放在它所修饰的名词之后,不定式表示的行为通常是未来的行为,它们常和被修饰的词有动宾关系,主谓关系和修饰性关系. 1). 动宾关系: I have a lot of work to do.Give me a piece of paper to write on. 2). 主谓关系: She is the best person to finish the work.Women and children were the first to get into the lifeboat. 3). 修饰性关系(同位),它所修饰的词多为抽象名词.need, time, way, right, chance, courage, reason, wish, movement.eg: There is no need for him to come.He has no time to read the book.,4. 做状语: 1). 目的状语: 可放于句首,也可放于句末, 前面可加in order/so as/soas to表强调. eg: He went to see the artist himself.He stopped to have a look.He ran so fast as to get to school in time. 2). 结果状语:主要用在enough to/tooto/only to结构中。 eg: The question is too difficult to answer.They worked hard enough to finish their work.,3). 原因状语: 主语+系动词+adj.+ to do a). 表感情的adj.有: happy, surprised, pleased, glad, sorry, anxious(忧虑), disappointed, careful, afraid, wrong. eg: Im very happy to see you.He was afraid to leave him home. b). 说明句中主语在哪个方面存在形容词所表示的情况时,即与句中主语构成逻辑上的动宾关系，主动表被动. interesting, difficult, easy, important, possible, expensive, dangerous, useful. eg: The question is easy to answer.He is difficult to teach.,5. 做宾语: 不定式做宾语的情况，一般表示将来的行为,这时谓语和不定式的动作都是主语发出的. 1). 下列动词只能加不定式做宾语. . plan, choose, manage, learn, pretend, agree, decide, refuse. promise, prepare, offer, fail, hope, wish, expect, ask;demand, want, hesitate,2). 不定式做动词tell, teach, know, show, find out, discover, see(understand)的宾语时,不定式前常加连接代词who, which, what和连接副词how, when, where构成不定式短语做宾语. eg: I dont know how to get there. 注: why不能与不定式连用. 3). begin, start, continue 后接不定式,动名词意思一样. 4). like, love, hate, prefer动名词表经常性的动作，不定式表一次性动作.,5). remember, forget, regret后动名词表已经做过的动作,不定式表没有做过或将要做的动作. 6). stop, try, go on, mean, be afraid, propose 后两者都可, 但意义不同.propose to do计划,打算做propose doing 建议做 7). a). prefer doing to doing prefer to do rather than dob). its no use doingits useless to doc). be worth doingbe worthy of being donebe worthy to be done,6. 做宾补(与宾语之间的关系实际上是逻辑上的主谓关系) 1). 有些动词(短语)必须接to的不定式做宾补 talk, ask, warn, want, allow, permit, order, advise, force, beg, cause, encourage, invite, persuade, get, require, prefer, call, leave, expect, use(allow/permit/advise doing sth),四, 不定式的时态和语态 时态: 三态 to do/ to be doing/ to have done 一般式表示的动作通常与句中谓语动作同时或在其后发生 eg: We saw him go to the shop. 进行式表示不定式的动作正在进行. eg: He pretended to be working hard. 完成式表示不定式动作在谓语动作/状态前发生. Im glad to have seen your mother. eg: I happened to have read the book.,动词不定式To 的几种常见的省略形式,非谓语动词历来是高考中的重点，不定式结构在考点中常占很大比重。其中TO的用法很复杂，现就TO在一些结构中常被省略的情况作如下小结。 1感官动词和使役动词在主动语态中不需要带to，即我们常说的“一觉二听三让五看”：feel, listen to 、hear ,let、make、have, see、watch、notice、observe、look at. He noticed Tom take a branch of flowers in his hand. 他注意到汤姆手中拿着一束鲜花。 The teacher has us write a composition every week. 老师要我们每周写一篇文章。 注： 除let 外其他在变成被动语态时要加上to。 The person was seen to enter the shop by us . 我们看见那个人进了那家商店。,2当主句中存在do 动词的任何形式， 介词but 后就省去to, 而只接do(只是do动词，不能是其他行为动词) 其结构为can not do but（do)，can not help but (do)不得不等句型， eg. She can do nothing but/except sing. 她除了唱歌什么也没做。 There is nothing he could do but play all day long。他除了整天玩，别无它事可做。 I couldnt do anything but sleep I did nothing but wait He had nothing to do but cry. I had no choice but to sleep,3不定式做help后的宾语补足语或宾语时，可带to也可不带。 Can I help（to） carry it for you? 我可以帮你搬吗？ I helped him（to） mend the bike. 我帮助他修理自行车。 4在had better，would rather，rather than之后省略to。 Youd better not tell him the news . 你最好不把这个消息告诉他。 Rather than wait anyone, I decided to go home by taxi. 我决定乘出租车回家而不愿等候任何人。,学习动词不定式时要特别注意以下几点： 一、后接不定式的动词 1.后接不定式做宾语的动词hope, agree, dare, decide, determinebegin, start, refuse, prepare,offermanage,try, aim, forget, remember ，chooseseem, pretend, learn, love, hate等。 (可记：希望同意敢决定，开始拒绝备提供，设法瞄准忘记选，似乎假装学爱憎。) 2.后接不定式作宾补的动词 permit,request,allow,command,tell,invite,cause,encouragewarn,adivse,persuadeforce,order,remind,teach等。 (可记首字母：practice wap fort 实践攻克堡垒。)3.后接不定式既作宾语又可作宾补的动词 ask,beg,like,preter,help,promise,wish,want,expect等。 （可记：请求、愿、助、诺、希望。）,