动词不定式的用法二、动词不定式充当的句子成分不定式具有名词、动词、形容词和副词的特性，在句中可以作主语、宾语、表语、定语、状语和宾语补足语。
（一）、作主语：1、不定式作主语多表示具体的、一次性的动作；动名词作主语多表示经常性的、习惯性的动作。
如：To swim today is a good idea Eating too much is bad for your health.2、不定式作主语时，常可以用it 作形式主语，而将真正的不定式主语后置。
但要熟记以下使用动名词作主语的句型：常用动名词作主语的句型有：It is/was +There is/was +更糟糕的）注意：There is no need for sb to do sth.2. 一般情况下，不定式作主语，谓语动词一般用单数形式。
如：To see is to believe.3. 当主语为不定式时，表语也用不定式来表示一致性。
如：To see is to believe.（二）、作宾语1、不定式作宾语通常表示具体的、一次性的动作。
如：Tom likes playing football, but he likes to play basketball today.但需要牢记以下的动词只使用v-ing 为宾语：avoid, miss, delay / postpone, suggest / advise, finish, practice, enjoy/appreciate, imagine, resist, admit, deny, envy, escape / envy, risk, pardon / excuse, keep / keep on, stand, mind;有些动词后面只能接不定式作宾语,如：decide/determine, learn, want, expect/hope/wish, manage, refuse, care, pretend, offer, promise, choose, plan, agree, ask/beg, help, wait, happen, afford, fail, threaten;有些动词短语后面也只能接动名词作宾语,如：lead to, get down to, look forward to, pay attention to, stick to，be addicted to, adjust/adapt to, devote to，object to，get to/be used to（习惯于），prefer…to…, can't stand（忍不住），give up，insist on，keep（on），put off，be worth，be/keep busy，have difficulty/trouble/problem（in），feel/look/seem like，set about，depend on，prevent sb. from，succeed in, thank you for, apologize for；有些动词后面既可以接不定式作宾语，又可以接动名词作宾语，如：continue，begin，start，prefer，like，love，hate，forget，go on，mean，regret，remember，stop，try，need, require, want 等。
2、不定式一般不作介词的宾语（但but/other than，except除外）。
如：I have no choice but to accept the fact.①如果此时谓语动词含有do的各种形式，不定式要省去to.I have done nothing except eat and sleep this week.I couldn't do anything but wait here.②在下列短语后，but之后只能跟不带to的不定式。
His father could do nothing but wait for the doctor to arrive.We would do anything but confess(承认)our guilty.我们决不承认有罪。
She couldn't help but laugh at his clothes.她情不自禁地大笑他的着装。
I cannot but admire(钦佩) his courage.I could not choose but love her.我不禁爱上了她。
3、有少数动词，如find，think，consider，make，feel等接不定式作宾语且其后面有宾语补足语时，常用it作形式宾语，而将真正的不定式宾语后置。
如：I think it better to start off right now.4、在动词hope, want, plan, expect, intend, mean, promise, wish的过去式之后用不定式的完成式作宾语，表示本来希望或打算做而未做的事，常可以与had + 这些动词ed + to do…结构互换。
如：I hoped to have met you at the airport, but I was too busy. = I had hoped to meet you at the airport, but I was too busy.（三）、作表语1、不定式作表语表示具体的、一次性的动作。
如：My job today is to water all the flowers in the garden.2. 注意主语和表语的一致性，当主语为不定式时，表语一般也用不定式：如：To see is to believe.注意：如果主语部分的谓语动词或非谓语动词中含有do，那么作表语的不定式可以省去to。
如：The only thing he could do was（to）tell the truth.（四）、作定语1、不定式作定语多表示未来的动作；2、不定式作定语常常放在它所修饰的词之后；如：There is nothing to worry about.3、不定式和分词作定语，用来说明被修饰词的动作，与被修饰词之间有逻辑关系（主谓或动宾关系）；如：the way to do the work，the nurse to take care of the children4、常用不定式作定语的情况：(1) 当名词被the first，the last等序数词、形容词最高级或no，all，any等修饰时，常用不定式的一般式作定语，而不管动作是否已经完成。
如：He is the only person to know the truth.She is always the first to come and the last to leave.He has no right to do it.(2)不定式常用来修饰表示抽象意义的词，常见的有right（权利），ability，chance，answer, belief, reason, reply，attempt，key，way，moment，time, idea, fact, excuse, promise, 等。
如：Could you at least make an attempt to smile，Jim？（吉姆，你起码试着笑一笑，行吗？）Do you have the ability to read and write in English？5. 不定式作定语与被修饰的名词或代词之间常常构成的几种关系。
（1）逻辑主谓关系：不定式和它所修饰的名词或代词构成主谓关系。
如：He is the first person to come and the last one to leave.注意：此时不定式常常用主动形式。
（2）逻辑动宾关系：不定式和它所修饰的名词或代词构成动宾关系。
如：He has nothing to do.注意：A、此时要求不定式为及物动词（如果是不及物动词，或者不定式所修饰的名词或代词是不定式动作的地点、工具等，不定式后面必须有相应的介词，即“不及物动词+ 介词”）；并且不定式常常也用主动形式。
如：He has nothing to do. There is nothing to worry about. The boy cried as he had no children to play games with. There is no room to live in. I haven't a pen to write with.B、不定式修饰名词time，place，way时，不定式后面的介词习惯上要省去。
如：He had no money and no place to live.（不是no place to live in）C、这种“动词不定式+ 介词”修饰名词/代词，可以转换成“介词+ 关系代词（which，whom）+ 不定式”。
如：Jim had only ten yuan to buy a present with.=Jim had only ten yuan with which to buy a present （3）同位关系：不定式与被修饰的名词或代词构成同位关系。
如：His wish to become an artist has never come true（五）、作状语1、不定式多作目的、结果、程度和原因状语。
如：She swept to hear the bad news.I’m very glad to hear the good news.He tried his best to arrive there only to find some waste paper.He is old enough to go to school.She is too tired to do the job.2、不定式作状语（多作目的、结果、程度和原因状语）：（1）作目的状语（可以放在句首或句中，在句中作目的状语时一般不用逗号隔开）：He stopped to have a rest.=To have a rest，he stopped.注意：in order to和so as to后面都可以接不定式作目的状语，但in order to可以放在句首或句中，而so as to则只能放在句中。