定义 用法 动词不定式是非谓语动词的一种，它没有人称和数的变化，在句子中不能独立作谓语，但它仍保持动词的特点，既可以有自己的宾语和状语。 动词不定式具有名词、形容词和副词的特征。因此在句中可以做主语、表语、宾语、宾语补足语、定语和状语。

基本形式 not to do to be done to do 一般形式 否定形式 被动形式 一般式表示的动作或状态，发生在谓语动词表示的动作或状态的同时或之后 否定形式 not to do 被动形式 to be done

to have done to be doing 进行形式 进行式表示的动作或状态，与谓语动词表示的动作或状态同时发生 完成形式 完成式表示动作或状态，发生在谓语动词表示的动作或状态之前

一、不定式做主语： 1、不定式做主语一般表示具体的某次动作。 e.g: To finish the building in a month is difficult work. To do such things is foolish. 注: 1 不定式作主语时,谓语用单数 2、当主语较长，谓语较短时，常用it做形式主语，而将不定式放到谓语的后面。

it做形式主语，不定式放在谓语动词之后常用于下列结构中： (1) It is/was +adj.+of sb. to do… 注意：在此句型中，adj. 只能用可以修饰 人物的形容词。 例如: kind nice good brave clever wise stupid foolish honest careless cruel generous eg: It is brave of him to save the girl in the water. It was careless of her to make such a mistake.

(2) It is +adj.+for sb.+to do… 某物的性质。 例如：difficult, wonderful, meaningful, painful, useful Eg: It is not difficult for us to learn English well. It is right for him to work here.

(3) it is +a +名词+ to do 例如: pleasure pity duty shame crime 等 Eg : It is a duty to plant trees every day . 注: 在感叹句和疑问句中只能用it作形式主语 Eg : What fun it is to jump into a lake in summer! How long did it take you to finish the work?

一、不定式做表语： 不定式作表语常表示将来的动作 1.主语是以aim duty hope idea intention mistake plan proposal job suggestion wish purpose task 等为中心词的名词词组 或以 what 引导的名词性从 句表示，后面的不定式说明其内容 eg : My idea is to climb the mountain from the north. Your mistake was not to write that letter. What I would suggest is to start work at once.

2主语和表语都是不定式（其含义往往一是条件，一是结果） Eg : To be kind to the enemy is to be cruel to the people. To do that would be to cut the foot to fit the shoe.

3 不定式常用在系动词 be, seem, appear, get, remain become , look , sound , taste , smell , feel , 等后作表语． Eg : The plan seems to have been changed . 4 在某些句型中，当主语部分有动作动词do时，作表语的不定式可以省略符号 “to”，例如： All you have to do is (to )press the button. The only thing I can do is (to) give you as much help as I can.

三 动词不定式作宾语 1、“动词 + 带 to 的不定式结构” 常用动词有: like wish hope want 三 动词不定式作宾语 1、“动词 + 带 to 的不定式结构” 常用动词有: like wish hope want try begin start mean agree refuse promise pretend ask choose decide forget hope learn want would like intend demand expect fail offer help hate attempt determine try manage remember prepare plan 等 Eg : We hope to get there before dark. The girl decided to do it herself.

动词+疑问词+不定式 2 不定式即可作动词的宾语也可作介词的宾语. 不定式作介词的宾语时,介词之后一般不直接接不定式，一般都是:疑问词+不定式作宾语. 这种不定式结构接近一个名词从句 动词+疑问词+不定式 Eg : I’m worrying about what to do next. Marx gave some advice on how to learn a foreign language.

这类动词常见的有： tell advise show teach find out decide discuss learn forget inquire know explain remember see understand wonder 等。 疑问词（也称连接代/副词）有：what where who(m) when how whether Eg : I don’t know what to do / where to go / who(m) to ask / when to stop / how to get there. I haven’t decided whether to sell it or not. We must find out what to do next / where to put it.

注1 ：如果作宾语的不定式结构后面还有自己的补语，则应使用先行 it，把不定式后置 eg : I find it difficult to understand him. We thought it wrong not to help her. They found it impossible to get everything ready in time. 注2 ：不定式结构一般不可作介词宾语, 只有在个别场合, 即在含有否定意义的带有介词 except 或 but (=except) 的结构中才能这样用. Eg : He seldom comes except to look at my pictures.

do nothing but / except 后的不定式不带to. 注意不定式符号的省略问题！ do nothing but / except 后的不定式不带to. 需要注意的是,此句型中but/ except 前必须要有实义动词do时，but / except后的不定式to才能省略，否则to则不省.我们用一句话概括就是： 有do无to，有 to无 do． Eg : She has no choice but to wait for the news. He could do nothing but wait. He will do anything for you except lend you money. .

记住要做某事； 记得曾经做过某事 remember to do remember doing 忘记要做某事 忘记曾经做过某事 注3 有些动词既可跟不定式作宾语，也可跟动名词作宾语，但含义不同 记住要做某事； 记得曾经做过某事 忘记要做某事 忘记曾经做过某事 停下来去做某事 停止做某事 继续做另一件事 继续做原来在做的事 remember to do remember doing forget to do forget doing stop to do stop doing go on to do go on doing

Eg : I remember seeing you somewhere before. Please remember to turn off the light when you leave. 我记得以前在哪儿见过你。 离开时请记得关好灯。

四 不定式结构作宾语补足语 1、只能用不定式结构作宾语补足语的动词 四 不定式结构作宾语补足语 1、只能用不定式结构作宾语补足语的动词 ① 表示“希望”“愿望”等心理状态的动词，如：wish, desire, expect, love, prefer, encourage, trust 等。 Eg : What do you desire me to do? The director preferred her to act the old lady. 含有“让”“允许”“促使”“致使”等祈使意义的动词，如：let, allow, permit, decide, mean, lead, bring, put, hurry, cause, 等。 Eg : We mustn’t let this (to) happen again. His father put him to mind the sheep.

③ 带有“请求”“恳求”等感情色彩的动词，如：ask, desire, invite, beg, request, worry 等。 Eg : He begged me not to tell his father about it. She was always worrying her father to take her to Paris. ④ 含有“建议”“劝告”等意义的动词，如：advise, persuade, call on, urge 等。 Eg : He urged us to accept the compromise. The dentist advised me to have the bad tooth pulled out.

⑤ 含有“命令”“强迫”“禁止”等意义的动词，如：order, command, require, charge, tell, make, oblige, force, drive, forbid, warn 等。 Eg : He required us to keep it a secret. The doctor ordered him to stay in bed for a few days. I warn you not to do that again. ⑥ 其他还有：help, teach, show, assist, report, bear, wait for, train, depend on 等。 Eg : He promised to teach me to swim. We should train them to make use of reference books. We are waiting for the train to stop.

2、既能用不定式结构又能用现在分词作宾语补足语的 动词： △ see, watch, notice, look at, hear, listen to, observe, feel, have; △ imagine, find, discover, like, want, understand, hate, bring, get, leave, set Eg : Did you see anyone enter the house? Don’t imagine yourself to be always correct. We find him to be dishonest.

注 ①：有些动词用不定式与用现在分词作宾语补足语，所表达的意义是有差别的。 不定式表示一次性动作或动作的完成（即全过程） 现在分词表示动作正在进行,即：谓语动词所表示的 动作发生时，现在分词所表示的动作正在进行 Eg : Did you see anyone enter the house? He saw his father talking with his teacher. I once heard him sing this song. She heard Mr. White singing in the next room.

但当以上的动词用于被动式，to要还原： 注②：使用不定式作宾语补足语时，在有些动词后面，不定式符号to 应当省略 “看”： see, look at, observe, watch, notice “听”：hear, listen to “感觉”：feel 使役动词：have, make, let 但当以上的动词用于被动式，to要还原： They saw the boy fall suddenly from the tree. The boy was seen to fall suddenly from the tree.

需要注意have, make的用法： have, make 用做使役动词 表“让，使，允许”等意，其后的不定式作宾补时，才可 省to． 用作一般实义动词 have表示“有”，make表示“制造”，“做”等意义， 且后面的不定式作目的状语，定语等时，不定式符号to不能省． “允许” “有” “使” “做” Eg : I won’t have him cheat me.　　 I have a lot of work to do.　　 His story made us laugh.　　 Father made a kite for his son to fly.　

△feel 在使用 to do 型不定式作宾语补足语时不带 to； 在使用 to be 型不定式时，要带 to， Eg : He felt them to be right. Did you feel the earth shake? △ help 一词在使用不定式作宾语补足语时，可以带 to，也可以不带 to Eg : Do you often help your mother (to) do the housework?

五.作定语:(常常表示将来的动作) （不定式作定语须放在被修饰的名词 或代词的后面） 1.不定式与被修饰的词有动宾关系 e.g: Have you got anything to do this evening I have some fiends to invite.

当名词被 the first , the last, the only 等序数词 以及形容词最高级修饰时，常用不定式 作定 语，而不管动作是否已完成． Eg : He is the only person to know the truth. She is always the first to come and the last to leave.

2.不定式用于说明被修饰的名词或代词的内容，相当于同位语，可转换成同位语从句。 e.g: I have no chance to go abroad. = I have no chance that I will go abroad.

3作定语的不定式与被修饰的名词或代词存在着两种 逻辑关系，即被修饰的名词和代词是不定式的 逻辑主语 或逻辑宾语． Eg : Alice is always the first student to come to school. The teacher gave me some English books to read. The meeting to take place here tomorrow is going to discuss the problem of pollution. Mr. Brown has a large family to　support．　　

当被修饰的名词或代词是不定式逻辑上的宾语，而该不定式动词又是不及物动词时，应在该动词后加上一个介词以形成逻辑上的动宾关系． Eg : Please pass me some paper to write on. There’s nothing for us to worry about. She has a nice pen to write with. He bought a flat for the family to live in. An office to work in /A child to look after A river to swim in

六、不定式做状语 修饰动词、形容词、副词等 表示目的、原因、结果、 条件等。 1、表目的 e.g:To learn a foreign language well, you must try your best.. He came here to attend an important meeting.　　　

注①：不定式结构表示目的时，通常句子的主语就是 它的逻辑主语 Eg : He bought a bicycle to go to town more quickly. He went home to see his mother. eg : He opened the door for the children to come in. They sent a man to mend the window. 例外的情况

注②：为了强调表示目的的不定式结构，特别是在不定式结构前有否定词 not 时，通常可以在不定式符号 to 之前加上 in order 或 so as Eg : He came here in order to see Charlie. He shouted and waved so as to be noticed. He went early in order not to miss the train. I turned the radio down so as not to disturb him

注③：表示目的的不定式可以置于句首，这也是区别于 其他功能的标志之一。 但是，置于句首表示目的的不定式之前可以加上 in order，但却不可以加上so as ， Eg : To draw maps properly, you need a special pen. (In order to draw maps properly, you need a special pen.) To get the best results, use clean water.

2、表结果 不定式结构表示结果更常见于下列句型： ① so …as to … Would you be so kind as to lend me your bicycle / tell me the time? ②    such (…) as to … I’m not such a fool as to believe that. ③    enough to … The boy is old enough to go to school. ④    too … to … His eyesight is too poor to read such small letters.

注意：下列句子中的不表示结果，也无否定含义： I’m only too glad to go. = I’m very glad to go. I shall be only too pleased to get home. = I shall be very pleased to get home. 〖 only too (adv.) 极; 非常; 太;很 〗

eg : She woke early to find it was raining. ☆☆不定式结构还能表示一个随后发生的动作，相当于一个并列限定动词词组，这种不定式结构也表示结果 eg : She woke early to find it was raining. He got home to learn that his father was ill. 这种表示结果的不定式结构具有下列几个特点： 1 不定式所表示的动作是随后发生的，相当于一个限定动词词组，如： He arrived late to find the others had gone home. He arrived late and found the others had gone home. .

2 不定式所表示的结果往往含有“令人意想不到”的意味，其中以“使人不愉快的结果”较为常见。 （有时也可以表示令人愉快、惊喜的结果） Eg : He went home to find his old friend George waiting for him. 3  不定式之前有时可以加上only或but only，以加强语气 Eg : He got to the station only to be told the train had gone. They lifted a rock only to drop it on their own feet.

注：不定式结构表示结果或表示目的，往往形式相似， 这时，须根据词汇意义认真加以区别， 试比较： He arrived late to find the others had gone home. ( = He arrived late and found the others had gone home.) He arrived late to avoid meeting Robert. ( = He arrived late in order to avoid meeting Robert.) He got to the station only to be told the train had gone. He went to the station to inquire about the times of trains. ( = He went to the station in order to inquire about the times of trains.)

3. 表示原因：（不定式所表示的动作先于谓语动词 的动作） eg :I wondered to hear her voice in the next room . = I wondered because I heard her voice in the next room . She cried to see him in that condition . = She cried because she saw him in that condition .

注意 在there be结构中，作定语用的不定式如修饰主语时，即使表示被动的意义，也可用主动式来表示． There is a lot of work to do/to be done. Hurry up! There’s no time to lose/to be lost. There are three letters to answer/to be answered this morning.

不定式的完成式表示动作发生在谓语动词之前． I’m glad to have seen your father. She seemed to have heard of it already. So you are the one to have cleaned all these rooms.

主动形式表被动意义的不定式 主语＋be +adj. +to do E.g.: The question is very difficult to answer. The problem is difficult to deal with. 主语＋be +adj. +to do 能用于此句型的形容词有：difficult ,easy, comfortable ,fit, hard, pleasant, tiresome(使人疲劳的) ,interesting, nice , heavy, dangerous, light, important, etc.

主语+be +adj. + enough +to do E.g.: The box is light enough to carry. The river water is warm enough to swim in. 主语+be +adj. + enough +to do E.g.: The books seemed too heavy to carry. The ice is too thin to skate on. 主语+be +too +adj. +to do