动词不定式、动名词用法要点讲解

#19968;、作主语
　　⒈不定式作主语
　　动词不定式作#20027;语时，句子的谓语动词常#29992;单数，其位置有以下两种：
　　(1)把不定式置于句#39318;。如：
To get there by bike will take us half an hour.
　　(2)用it作形式主语，把#30495;正的主语不定式置于#21477;后，常用于下列句式#20013;。如：
　　①It#65291;be＋名词＋to do
　　It's our duty to take good care of the old.
　　②It takes sb some time to do
　　How long did it take you to finish the work？
　　#9314;It＋be＋形容词＋for sb＋to do
　　It is difficult for us to finish writing the compositionin a quarter of an hour.
　　④It＋be＋形容词＋of sb＋to do
　　It is stupid of you to write down everything the teachersays.
　　⑤It seems(appears)＋形#23481;词＋to do
　　It seemed impossible to save money.
　　在句型③中#65292;常用表示客观情况的#24418;容词，如：difficult，easy，hard，important，impossible，necessary 等；在#21477;型④中，常用careless，clever，good，foolish，honest，kind，lazy，nice，right，silly，stupid，wise等 表示赞扬或#25209;评的词。在不定式#21069;的sb，可看作其#36923;辑主语。这一句式有时相当于Sb is＋形容词＋to do句式 ，如：It'skind of you to help me with my English.=You are kind to helpme with my English.
　　⒉动名词#20316;主语
　　Learning without practice is no good.
　　动名词作主语#26102;，也常用It句式。如：
①It's no good(no use，fun，a pleasure，a waste of time) doing…
　　It's no good reading in dim light.
　　It's no use sitting here waiting.
　　②It's＋形容词＋doing
　　It's dangerous swimming in the sea in windy days.
　　这样用的形容词#26377;expensive，nice，tiring等，但important，necessary则不适用于这种结构，应用不#23450;式 代替，如：It'simportant for you to keep fit.
　　③There is no doing
　　There is no saying what will happen next.
　　#22312;这一结构中，动名词后#24120;带宾语，相当于"It's impossible to…"结构。
　　⒊动#35789;不定式和动名词作#20027;语的区别
　　①不定#24335;作主语经常表示具体动#20316;，常与特定的动作执行者联#31995;在一起；而动名词作主语经常表#31034;抽象动 作#65292;经常不与特定的动作执行者联系在#19968;起。如：
　　It's no good eating too much fat.
　　It's no good for you to eat so much fat.
　　②动名词结构作主语，可以#29992;名词或代词属格形式作#36923;辑主语。如：
　　It's no use your pretending that you didn't know the rules.
二、作宾#35821;
　　⒈不定式作宾语
　　①以下动#35789;后，只能跟不定式作宾语。如：agree，ask，aim，arrange，choose，decide，demand，expect，fail ，help，hope，lean，long，
manage，offer，plan，prepare，pretend，promise，refuse，wish等，这些词大部#20998;可接th at引导的#20174;句。如：
　　I decided to ask for my money back.
　　I decided that I would ask for my money back.
　　When our visit to the farm was over，we expected to startback on foot.
　　When our visit to the farm was over， we expected that wewould start back on foot.
　　②当复合宾语中的宾#35821;是不定式时，先用形式宾语it代替不定式，把不定#24335;置于补语之后，即：主语＋动 词＋it＋补语＋to do句#24335;。如：
　　We think it quite important for us to learn a foreignlanguage well.
　　He feels it his duty to help the poor.
　　③介词but，except，besides to do(do)
　　在#36825;种句型中，如介词前有动词do，后面应接不带to的不定式#65307;如无do，则接to不定式，即带do不带to， 带to不带do#12290;如：
　　The enemy soldiers had no choice but to give in.
　　On Sunday afternoon I had nothing to do but watch TV.
⒉#21160;名词作宾语
　　①以下动词后，只#33021;接动名词作宾语，如：admit，appreciate，consider，delay，enjoy，finish，keep，imag ine，mind，miss，practise，resist，risk，save，suggest，don't mind，give up，insist，on， put off等。如：
　　I suggest spending our summer vacation in a seaside town.
　　You must give up smoking， for it does too much harm toyour health.
　　②动名词作介词的#23486;语
　　I should go to attend the birthday celebration instead of staying at home.
　　What about inviting Li Jun to make a speech？
　　动名词前的介#35789;有时可以省略，如：have difficulty(in)doing，have no trouble(in)doing，lose no ti me(in)doing，prevent/stop…(from)doing，there is no use(in)doing等。
　　⒊部分动词后面#65292;既可接动词不定式，也可接#21160;名词作宾语，意义不变#12290;如：begin，continue，start，hat e，like，love，need，require，want等。
　　在need，require，want后接-ing形式#65292;表示被动意义，也可接不定式，#20294;要用被动形式，如：Your handwr iting needs improving(tobe improved). hate，love，like接不定式表示特定的未来#20107;件，接动名词表示目前 正在进行的活动或#19968;般的行为。
　　在下#21015;情况下，一般要用不定式：
　　①hate，like，love前有would(should)时，如：I'd like to have a cup of coffee.
　　②当谓语动#35789;begin，continue，start等#26159;进行式时，如：Thestudents are starting to work on the di fficult maths problem.
　　③begin，continue，start与know，understand等状态动词连用#26102;，如：I soon began to understand what
　　was happening.
　　⒋advise，allow，encourage，forbid，permit等动词后接#21160;名词作宾语，或带不定式作#23486;语补足语。如：
　　Our teachers don't permit our swimming in the lake.
　　Our teachers don't permit us to swim in the lake.
　　⒌部分动词后接不定式或动名#35789;时，意义差别较大，应根据句#23376;语境选择使用。
　　①forget，remember，regret后接不定#24335;，表示现在或未来#30340;动作，接动名词表示动作已经#21457;生。如：
　　Don't forget fo post the letter for me.
　　Have you forgotten meeting her in Beijing Airport？
　　Remember to close the windows before you leave.
　　I remember writing him a letter a year ago.
　　We regret to tell you that all of you are not invited toattend the meeting.
　　They regretted ordering these books from abroad.
②mean to do 打算做某事
doing 意味着……
　　I meant to catch up with the early bus.
　　This means wasting a lot of money.
③try to do 设法尽力#20570;某事
doing 试着做#26576;事
　　You should try to overcome your shortcomings.
　　Try working out the physics problem in another way.
④stop to do 停下一件事去做另一件事#65288;不定式作目的状语）
doing 停止做某事
On the way to the airport，I stopped to buy a paper.
　　You'd better stop arguing and do as you are told.
　　⑤can't help doing 禁不住……
to do不#33021;帮助干……
　　They couldn't help jumping up at the news.
　　Sorry I have lots of work to do.So I can't help to make up the room for you.
　　⑥go on to do 做不同的事或#19981;同内容的事
doing #32487;续不停地做某事，指同一动作#30340;继续
　　He went on to talk about world situation.他接着又谈了世界形#21183;。
　　We'll go on fighting so long as there is oppression inthe world.
　　⑦leave off to do 离#24320;某地去干什么（目的状语#65289;
doing停下某事
　　It's time to leave off talking and to start acting.
　　They left off to go fishing.
三、做表语
　　不定#24335;作表语表示具体动作#25110;将来动作；动名词作表语表示#25277;象的一般行为。
　　①To be kind to the enemy is to be cruel to the people.
　　②My chief purpose is to point out the difficulties ofthe matter.
#9314;What I would suggest is to put off the meeting.
　　当主语和表语都是不#23450;式时，其含义一是条件#65292;一是结果（例①）。#24403;主语是aim，duty，hope，idea，mista ke，plan，purpose，suggestion等为#20013;心词的名词词组（例②#65289;时，或以what引导#30340;名词性分句（例③），不定 式说明主语的内容#12290;
　　④Our work is serving the people.
⑤What he likes is taking a walk after supper.
　　⑥The story told by Mr.Wang is interesting.
　　④⑤句#21160;名词作表语，与主语部分可以#36716;换，如Serving thepeople is out work，而⑥句中#26159;现在分词作 表语，说#26126;主语的性质、状态，现在分词#20855;有形容词的各种特征，另外#65292;动名词作表语还应与进行时#24577;区别开 来#12290;
四、作定语
　　⒈不定式作定语
　　不定式在句中#20316;定语，置于被修饰的名词或代#35789;之后。如：
　　①The next train to arrive is from Washington.
②Have you anything to be taken to your sister？
　　③Do you have anything to say on the question？
　　④Would you please give me some paper to write on？
　　⑤My wish to visit France has come true at last.
　　不定#24335;短语作定语和被修#39280;词之间表示以下关系#65306;
　　(1)表示将来#30340;动作（例①）。
　　(2)与被修饰词#20043;间有动宾关系，如是不及物动词#65292;则需加介词（例④）。
　　(3)与被修饰词之间有动#23486;关系，同时与句中#20854;它词之间又有逻辑上的#20027;谓关系时，尽管有#34987;动含义，却仍 用#20027;动语态（例③）；#22914;只有动宾关系，而#26080;逻辑上的主谓关系，则#38656;用被动语态（例②）。
　　(4)不定式作定语时#65292;一般可转换为定语#20174;句，例①to arrive=that will arrive。
　　⒉动名词作定语
①This passage can be used as listening materials.
　　②The reading room of our school library can hold 800people.
　　③All moving bodies have energy.
　　①②句动名词#20316;定语说明一种性能#65292;即：用来……的；#31532;③句为现在分词作定语，单#20010;分词作定语常置于 被#20462;饰词之前，与被修饰词#20043;间，可构成逻辑上的主谓关系，分#35789;短语作定语常置于被修饰词#20043;后。如：The man standing at the school gate is Professor Hua.
#20116;、不定式作补足语
　　⒈作宾语补足语
　　一#20123;及物动词除要求按#23486;语外，有时还需要有#23486;语补足语，说明宾语的行为、状态#12289;特征，这时意思才相 对完整。
　　(1)常要求不定式作宾补的动词有：allow，ask，advise，beg，cause，drive（强#36843;），encourage，expect，fo rbid，force，get，would like(love，hate)，order，permit，persuade，teach，tell，want，warn，wish等。如：
　　①Would you like me to give your regards to Mary？
　　②I want you to understand the whole passage clearly.
　　(2)部分动#35789;后常接to be＋形容词、名词短#35821;等形式，有时to be可省略，如：believe，consider，discov er，find(=consider)，feel(=think)，imagine，judge，know，prove，think，suppose，see(=understand)，understa nd等。
　　①We all believe John(to be)honest.
　　②I consider him(to be)one of the best biology teachers of No. 1 Middle School.
　　但当不#23450;式是完成式时，to不能#30465;略，如：We consider him tohave been foolish.
　　(3)感#35273;动词和使役动词后用作宾补的不#23450;式须省略to。
　　①I didn't hear anyone say anything about it.
#9313;They make the students do too much homework every day.
　　#36825;种句式在变为被动语态时，to不能省略，如第②句：Thestudents are made to do too much homework
　　every day.
　　(4)help，know后面#30340;"to"可有可无。如：
　　Would you please help me(to) fill in the taxform？
　　I've never known her(to)be late before.但：He was known to have been to France before.
　　(5)部分短语动词后，常接不定#24335;作宾补，如：
　　You may depend on them to be there early.
　　The Party calls on us to increase production and practise economy.
　　常这样用的#30701;语动词有：ask for，care for，call on，count on，depend on，wait for，long for#65288;渴望）， prepare for，wish for等。
　　#9353;作主语补足语
　　不定式#20316;主语补足语，和主语构成一种逻#36753;上的主谓关系。如：
　　①He was not allowed to enter the classroom for being late.
　　②The young university student is considered to have great promise. 免费论文下载中心
六、不#23450;式作状语
　　⒈作目#30340;状语
　　(1) ①I stayed there to see what would happen.
　　②Henry has decided to go to the hospital to be examinedby the doctor.
　　(2)有时#20026;了强调，不定式前可加in order或so as。如：
　　Bob took down my telephone number so as(in order)not toforget it.
　　有时为#24378;调目的状语可把in order to或不定式置于#21477;首，但so as to不能这样用。#22312;这种句式中不定式部 分可转换为so that，in order that，成为目的状语从句，如：
　　I stayed there so that (in order that)I could see whatwould happen.
　　(3)在部分表示感情#33394;彩的形容词、过去分词或动词#20043;后可接不定式，如：astonished，glad，happy，laugh ，pleased， sad，smile，sorry，surprised等。
　　①We are glad to hear the news.
　　#9313;I was surprised to see that a three-year-old baby could write so well.
　　#22312;部分形容词后接不定式，#29992;主动形式表示被动意义，这#31181;句型中的主语是不定式的#36923;辑宾语。如：The question raised by thestudent is difficult to answer.
　　The room is really comfortable to live in.
　　常这样用的形容词有：comfortable，easy，dangerous，difficult，expensive，fit，impossible等。
　　⒉作结果状语
　　We came home after our holiday to find our garden neat and tidy.
　　不定#24335;作结果状语还常用在下列句式#20013;。如：
　　①so…as to;such…as to
　　I'm not so stupid(a fool) as to put it in writing.我不至于愚蠢到会把它写下#26469;。
　　I'm not such a stupid fool as to put it in writing.
　　②enough…to
　　The speed is high enough for us to catch up with thefirst liner.
③only to
　　Jane hurried back only to find her mother dying inthehospital.
　　④too…to
　　I'm too tired to stay up longer.
　　但#22312;下列结构中，too…to并非是#8220;太……而不能……”之#24847;。如：
　　①I'm only too glad to have passed the exam.考试及格我太#39640;兴了。（too修饰glad to have…，相当 于very）
　　②We have too much to learn.#25105;们要学的太多了（不定式作定#35821;）。
　　⒊不定式短语还可作独#31435;成分，用于句首、句中或句末。如#65306;
　　To tell the truth，the play was a great disappointment tome.
　　常见的#30701;语有to be exact（确切地说#65289;，to begin with（首先），to do him justice（说#21477;对他公道的 话），to be sure（真的）等等。
七、动词不#23450;式、动名词的其它用法
　　⒈疑问词＋不定式#32467;构
　　疑问词who，what，which，when，where，whether，how后可接不定式构成#19981;定式短语，在句中作主语#12289;宾语、表 语等。如：
①When to leave for London has not been decided yet.
　　②Mr. Smith didn't know whether to leave or stay there.
　　③I asked Professor Xu how to learn English well.
　　④The question was where to get the medicine needed.
　　以上例句#20013;疑问词＋不定式部分#65292;均可转换为相应的从句形式。如#65306;①When we shall leave…③…how I
　　could learn…
　　经常在这种结构#20013;使用的动词有：consider，decide，discover，explain，find out，forget，hear，know，lea rn，observe，understand，wonder等。
　　⒉动词不定式的时态、语态
　　(1)时态
　　#9312;一般式：动词不定式一般式表示的#21160;作发生在谓语动词之后，有时表#31034;同时发生。如：
I hope to become a university student this year.（tobecome发生在hope之后）
　　We often hear Dick play the piano in the next room.（play和hear同#26102;发生）
　　②完成式：表示的动#20316;发生在谓语动词所表示的动#20316;之前。如：
　　I'm sorry to have kept you waiting.
We are too young to have seen the old society.
　　③#36827;行式：表示的动作#19982;谓语动词同时发生#12290;如：
　　The teacher happened to be correcting our papers when Icame in.
　　They seemed to be discussing something important.
　　(2)语态
　　如果动词不定式的#36923;辑主语是这个不定式所表示的动作#30340;承受者，不定式一般要#29992;被动语态形式。如：
It's a great honour to be invited to Mary's birthday party.（不定#24335;作主语）
It was impossible for lost time to be made up.（不定式作主语#65289;
I wish to be sent to work in the country.（不定式作#23486;语）
　　Can you tell me which is the car to be repaired？（#19981;定式作定语）
　　He went to the hospital to be examined.（不定式作状语）
　　在There be结构中，修#39280;主语的不定式可用被动，也#21487;用主动。如：There are still many things to t ake care of (to be taken care of).但有时两#31181;形式表达的意思不同，如：These is nothing to do now.( We have nothing to do now.) There is nothing to be done now.(We can do nothing now.)
　　⒊动名词的时#24577;、语态
　　(1)时态
　　#9312;一般式：动名词的一般#24335;所表示的动作可以是泛指，也可与#35859;语动词同时发生，或发生在谓语#21160;作之前 、之后。#22914;：
We are interested in collecting stamps.
　　I shall never forget seeing the Great Wall for the firsttime.
We are not afraid of dying.
　　②完成式所表示#30340;动作发生在谓语动词之前。如#65306;
　　Lmagine having travelled on the moon.
　　We were praised for having finished the work ahead of time.
　　(2)被动语态
　　①如果动名#35789;的逻辑主语为动名#35789;所表示的动作的承受者，#21160;名词要用被动语态，动名词的被#21160;语态有一 #33324;式与完成式之分。如：
　　The young man came in without being noticed.
　　He prided himself on having never been beaten in class.
　　②有些动词后的动名词用#20027;动形式，但表示被动意义。如：
　　The bike needs repairing.
　　If a thing is worth doing， it is worth doing well.
　　⒋在口语#20013;，为避免重复，常用"to"#20195;替不定式结构，有时甚至可以把to省略。如：
　　①—Did you go to visit the Great Wall？
—No，I wanted to，but there wasn't enough time.
　　#9313;—Would you like to come to a party？
　　—I'd love to.
　　③—Don't make any mistakes in your homework，will you？
—I'll try not to.
　　④—Try to be back by 12，won't you？
　　—OK，I'll try.
　　#21478;外，be going to，ought to，used to等也常用于#36825;一结构中。
　　⒌在why#24341;起的问句中，省略"to"#12290;如：
　　Why spend such a lot of money？
　　Why not wait for a couple of days？
　　⒍当两个或#26356;多作用相同的不定式并列使用时#65292;只在第一个不定式前#21152;"to"。如：
　　It's quite necessary for us to read more and have morepractice.
　　⒎"to"在#19979;列短语中是“介词”，后接#21160;名词或名词形式。如：
　　devote#8230;to，face up to（勇敢地面对）#65292;look forward to（盼望），object to（反对），take to#65288;养 成习惯，#23545;……感兴趣；开始#20174;事某种活动），be used to（#20064;惯于）等。
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