初中不定式todo的用法.doc

1. 不定式的用法-1.1 不定式作主语不定式作主语，往往用it作形式主语，真正的主语不定式放至句子的后面。 例如：Its so niceto hear your voice. 听到你的声音真高兴。Its necessary for youto lock the car when you do not use it.不用车的时候，锁车是有必要的。Its very kind of youto help us.他帮助我们，他真好。Itseemed selfish of himnot to give them anything.他不给他们任何东西，这显得太自私了。但是，用不定式作主语的句子中还有一个不定式作表语时，不能用It is to的句型。另外，这样的句子，不能用动名词作表语。例如：（对）To teachisto learn.（错）Itisto learn to teach.（错）To teachislearning.（错）Teachingisto learn. 典型例题The chair looks rather hard, but in fact it is very comfortable to _.A. sit B. sit on C. be seat D. be sat on 答案：B.如果不定式为不及物动词，其后应有必要的介词。当动词与介词连用时，常位于形容词+动词不定式结构的末尾。1.1.1 不定式做主语 Its for sb/Its of sb to do sth这样的句子中，由于表语形容词性质的不同，导致了不定式逻辑主语标志用for或of的区别。 1）for sb.句型中的形容词一般为表示事物的特征特点，表示客观形式的形容词，如easy, hard, difficult, interesting, impossible等：例如：Its very hardfor himto study two languages. 对他来说学两门外语是很难的。 2）of sb句型中的形容词一般为表示性格，品德，心智能力，表示主观感情或态度的形容词，如good, kind, nice, clever, foolish, right。例如：Its very niceof youto help me. 你来帮助我，你真是太好了。1.2 不定式作宾语有些及物动词用不定式作宾语，结构为动词+不定式。例如：affordaimagreearrangeaskdecidebothercarechoosedemanddesiredetermineelectendeavorhopefailhelplearnlong 渴望meanmanageofferplanpretendrefusetendundertakeexpecthateintend例如： The driverfailedto seethe other car in time. 司机没能及时看见另一辆车。Heofferedto helpme. 他表示愿意帮助我。2）有些动词除了可以用不定式作宾语，还用不定式作补语，即有动词+宾语+不定式的结构。例如：askchooseexpecthelpbegintendlike/loveneedpreferpreparewantwish 例如：Iliketo keepeverything tidy.我喜欢每件东西都保持整洁。 Ilikeyou to keepeverything tidy.我喜欢你使每件东西都保持整洁。Iwantto speaktoTom. 我想和汤姆谈话。Iwantyou to speak toTom. 我想让你和汤姆谈话。3）有些动词或动词词组可以用动词+疑问词+不定式的结构作宾语。例如：decideknowconsiderforgetlearnremembershow,wonderfind outtellinquireexplain 例如： Pleaseshowushow to dothat. 请演示给我们如何去做。 There are so many kinds of tape-recorders on sale that Idontknowwhichto buy. 有这么多的录音机，我都拿不定主意买哪一种。1.3 不定式作表语不定式可放在be动词后面，形成表语。例如：My workisto cleanthe room every day. 我的工作是每天清扫房间。His dreamisto be a doctor. 他的梦想是成为一名医生。1.4 不定式作定语不定式做定语通常要放在被修饰的词后，往往表示未发生的动作。例如：I have a lot of workto do.我有许多事要做。There was nothingto bring homethat morning. 那天早上（他回家时）两手空空。1.5 不定式作状语1）目的状语常用结构为to do , only to do（仅仅为了）,in order to do,so as to do,so（such） as to（如此以便）。例如： He ransofastas tocatch the first bus.他飞快地跑以便赶上第一班车。 I come here onlytosay good-byetoyou.我来仅仅是向你告别。2）作结果状语，可以表示没有预料到的或事与愿违的结果，不定式要放在句子后面。 I awoketofind my truck gone.我醒来发现箱子不见了。 He searched the room onlytofind nothing.他搜索了房间，没发现什么。3）表原因Im gladtosee you. 见到你很高兴。She wepttosee the sight.她一看到这情形就哭了。4）表示理由和条件He must be a fooltosay so.You will do welltospeak more carefully.1.6 不定式作补语1）有些有动词+宾语+不定式的结构。例如：动词宾语不定式He remindedmeto buy some eggs.THAT-从句He remindedmethat I had to buy some eggs.adviseallowcausechallengecommandcompeldrive 驱使enableencourageforbidforceimpelinduceinstructinvitelike/loveorderpermitmakelethavewantgetwarnpersuaderequestsendtelltrainurge 例如； Father will notallowus to playon the street. 父亲不让我们在街上玩耍。 The officerorderedhis mento fire.长官命令士兵开火。 注意：有些动词如make，have，get，want等可用不定式作做宾补，也可用分词作宾补。现在分词表达主动，也表达正在进行，过去分词表达被动。2)有些有动词+宾语+不定式的结构，不定式的动词往往是be，不定式一般可以省去。例如：considerfindbelievethinkdeclare（声称）appointguessfancy（设想）guessjudgeimagineknow 例如： Webelievehimto be guilty. 我们相信他是有罪的。 Weknowhimto be a fool. 我们知道他是个笨蛋。（to be 不能省去） 典型例题Charles Babbage is generally considered_ the first computer. A. to inventB. inventing C. to have invented D. having invented 答案：C. 一般没有consider+宾语+be以外不定式的结构，也没有consider+宾语+doing的结构，排除A、B、D。consider用动词be以外的不定式作宾补时，一般要求用不定式的完成式，故选C。3)有些动词可以跟there +to be的结构。例如：believeexpectintendlikelovemeanpreferwantwishunderstand 例如： We didntexpectthereto beso many people there. 我们没料到会有那么多人在那里。 You wouldntwantthereto beanother war. 你不至于想让另外一场战争发生吧。1.7 动词不定式的否定式在不定式标志to前加上not。例如： Tell himnot toshut the window。让他别关窗。She pretendednot to seeme when I passed by. 我走过的时候，她假装没看见。典型例题1）Mrs. Smith warned her daughter _ after drinking.A. never to drive B. to never driver C. never driving D. never drive 答案：Awarn sb to do sth.的否定形式为warn sb not to do sth.此处用的是否定词never.2）The boy wanted to ride his bicycle in the street，but his mother told him _. A. not toB. not to doC. not do it D. do not to 答案：Anot to 为not to do it 的省略形式。可以只用to这个词，而不必重复整个不定式词组。及物动词do后应有宾语，因此也B，D不对。2. 省略不定式符号“to”的情况1）情态动词 （ 除ought外） 后。 Shecantspeakto you. Heshouldgiveher some money. ShallItalkto him? Wouldyoulikea cup of coffee? Imightstayanother night in the hotel. Theymustleavebefore 10.00 a.m.2）使役动词let, have, make后，感官动词see, watch, look at, notice , observe, hear, listen to, smell, feel, find等后。注意：被动语态中不能省去to。例如：Isawhimdance. 我看见他跳舞。=He was seen to dance.The bossmadethemworkthe whole night. 老板让他们整夜干活。=They were made to work the whole night. Hesawherfallfrom the cliff. Weheardthemclosethe door. Theysawuswalktoward the lake. Shefeltthe spidercrawlup her leg. 3) 使役动词let, have, make后 Her parentsletherstayout late. Letsgoto the cinema tonight. Youmademeloveyou. Dontmakemestudythat boring grammar book!4）would rather，had better句型后 Wehad bettertakesome warm clothing. Shehad betteraskhim not to come.Youd betternotsmileat a crocodile!Wehad betterreservea room in the hotel.Youd bettergiveme your address.Theyhad betterworkharderon their grammar!5）Why / why no句型后6）help后可带to，也可不带to,help sb （to） do sth：7）but和except后。but前是实义动词do时，后面出现的不定式不带to。比较：He wants to do nothingbutgoout. 他只想出去玩。He wants to believe anythingbutto takethe medicine. 除了吃这药，他什么都信。8）由and, or和than连接的两个不定式，第二个to可以省去：9）通常在discover, imagine, suppose, think等词后作宾补时，可以省去to be。例如：He issupposed（to be）nice.他应该是个好人。典型例题1） - I usually go there by train. - Why not _ by boat for a change?A. to try going B.trying to go C.to try and go D.try going 答案：D. why not 后面接不带to 的不定式，因此选D。2） Paul doesnt have to be made _. He always works hard. A. learn B. to learn C. learned D. learning答案：B. make后接不带to 的动词不定式，当其用于被动时，to 不可省略。3. 不定式的时态和语态1）一般式表示的动词，有时与谓语动词表示的动作同时发生，有时发生在谓语动词的动作之后，例如: Heseemsto knowthis. 他似乎知道这事。 Ihopeto seeyou again. = I hope that Ill see you again.我希望再见到你。2）完成式:完成式表示的动作发生在谓语动词表示的动作之前,比如to have broken, to have seen, to have saved.例如: Someone musthave brokenthe window and climbed in. I would liketo have seenthe Taj Mahal when I was in India. He pretendedto have seenthe film. If Id seen the ball Iwould have caughtit.3）进行式表示动作正在进行，与谓语动词表示的动作同时发生。例如： Id reallyliketo be swimmingin a nice cool pool right now. Youmustbe joking! Ihappenedto be waitingfor the bus when the accident happened.4）完成进行式表示动作从过去开始并延续至说话的时候: (to) have been + 现在分词例如: to have been crying to have been waiting to have been painting The womanseemedto have been crying. You musthave been waitingfor hours! He pretendedto have been paintingall day.5）不定式的被动语态: (to) be + 被动式, 例如 to be given, to be shut, to be opened例如: I am expectingto be givena pay-rise next month. These doors shouldbe shut. This window oughtto be opened.4. 不定式的特殊句型-4.1 tooto1）tooto 太以至于。例如：He istooexcitedtospeak. 他太激动了，说不出话来。- Can I help you ? 需要我帮忙吗? - Well, Im afraid the box istooheavy for youtocarry it, but thank you all the same. 不用了。这箱子太重，恐怕你搬不动, 但还是谢谢你。2）如在too前有否定词，则整个句子用否定词表达肯定，too 后那个词表达一种委婉含义，意 为不太。例如：Itsnevertoolatetomend. 改过不嫌晚。（谚语）3）当too 前面有only, all, but时，意思是：非常 等于very。例如：Imonlytoopleasedtobe able tohelp you. 能帮助你我非常高兴。He wasbuttooeagertoget home. 他非常想回家。4.2 so as to1）表示目的；它的否定式是so as not to do。例如：Tom kept quiet about the accidentso as not tolose his job.汤姆对事故保持沉默是为了不丢掉他的工作。Go in quietlyso as not towake the baby.轻点进去，别惊醒了婴儿。2）表示结果。例如：Would you beso kind as totell me the time? 劳驾，现在几点了。4.3 Why notWhy not +动词原形表达向某人提出建议，翻译为：为什么不? 干吗不?。例如：Why nottake a holiday?干吗不去度假?