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高中英语语法复习讲义动词不定式一.相关知识点精讲:1. 不定式作补语1) 有些有动词+宾语+不定式的结构。例如: adviseallowcausechallengecommandcompeldrive驱使enableencourageforbidforceimpelinduceinstructinvitelike/loveorderpermitmakelethavewantgetwarnpersuaderequestsendtelltrainurge例如;Father will not allow us to play on the street. 父亲不让我们在街上玩耍。The officer ordered his men to 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,也表达正在实行,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,不定式一般能够省去。例如: considerfindbelievethinkdeclareappointguessfancy(设想)guessjudgeimagineknow例如:We believe him to be guilty. 我们相信他是有罪的。We know him to 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) 有些动词能够跟there +to be的结构。例如: believeexpectintendlikelovepreferwantwishunderstandmean例如:We didn't expect there to be so many people there. 我们没料到会有那么多人在那里。You wouldnt want there to be another war. 你不至于想让另外一场战争发生吧。2. 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:It's so nice to hear your voice. 听到你的声音真高兴。It's necessary for you to lock the car when you do not use it. 不用车的时候,锁车是有必要的。It's very kind of you to help us.他协助我们,他真好。It seemed selfish of him not 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。3. It's for sb.和 It's of sb.这样的句子中,因为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:It's very hard for him to 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,心智水平,表示主观感情或态度的形容词,如good, kind, nice, clever, foolish, right。例如:It's very nice of you to help me. 你来协助我,你真是太好了。用for还是用of 的另一种辨别方法:用介词for或of后面的逻辑主语作句子的主语,用介词前边的形容词作表语,造个句子。如果通顺用of,不通则用for。例如:You are nice.(通顺,所以应用of)。He is hard. (非所表达的意思,不通,因此用for。)4. 不定式作表语不定式可放在be动词后面,形成表语。例如:My work is to clean the room every day. 我的工作是每天清扫房间。His dream is to be a doctor. 他的梦想是成为一名医生。5. 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 work to do.我有许多事要做。There was nothing to bring home that morning. 那天早上(他回家时)两手空空。6. 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 ran so fast as to catch the first bus.他飞快地跑以便赶上第一班车。I come here only to say good-bye to you.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 awoke to find my truck gone. 我醒来发现箱子不见了。He searched the room only to find nothing. 他搜索了房间,没发现什么。3) 表原因I'm glad to see you. 见到你很高兴。She wept to see the sight. 她一看到这情形就哭了。4)表示理由和条件He must be a fool to say so.You will do well to speak more carefully.7.用作介词的toto 可以用作介词,也可用作不定式的标示。下面的to 都用作介词: admit toobject tobe accustomed tobe used tostick toturn to开始look forward tobe devoted topay attention tocontribute toapologize todevote oneself to8. 省去to 的动词不定式1) 情态动词 ( 除ought 外) 后。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:I saw him dance. 我看见他跳舞。He was seen to dance.The boss made them work the whole night. 老板让他们整夜干活。They were made to work the whole night.3) would rather,had better句型后4) Why / why no句型后5) help 后可带to,也可不带to, help sb (to) do sth:6) 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 nothing but go out. 他只想出去玩。He wants to believe anything but to take the medicine. 除了吃这药,他什么都信。7) 由and, or和than连接的两个不定式,第二个to 可以省去:8) 通常在discover, imagine, suppose, think等词后作宾补时,可以省去to be。例如:He is supposed (to be) nice.他应该是个好人。9.动词不定式的否定式在不定式标志to前加上not。例如:Tell him not to shut the window。让他别关窗。She pretended not to see me when I passed by. 我走过的时候,她假装没看见。10.不定式的特殊句型tooto1)tooto太以至于。例如:He is too excited to speak. 他太激动了,说不出话来。- Can I help you ? 需要我帮忙吗?- Well, I'm afraid the box is too heavy for you to carry it, but thank you all the same.不用了。这箱子太重,恐怕你搬不动。谢谢。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:It's never too late to mend.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:I'm only too pleased to be able to help you. 能帮助你我非常高兴。He was but too eager to get home. 他非常想回家。11. 不定式的特殊句型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 accident so as not to lose his job.汤姆对事故保持沉默是为了不丢掉他的工作。Go in quietly so as not to wake the baby.轻点进去,别惊醒了婴儿。2)表示结果。例如:Would you be so kind as to tell me the time? 劳驾,现在几点了。12. 不定式的特殊句型Why not"Why 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 not take a holiday? 干吗不去度假?13.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He seems to know this. 他似乎知道这事。I hope to see you again. = I hope that I'll see you again.我希望再见到你。2) 完成式表示的动作发生在谓语动词表示的动作之前。例如:I'm sorry to have given you so much trouble. 很抱歉,给你添了那么多的麻烦。He seems to have caught a cold. 他好像已经得了感冒。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:He seems to be eating something. 他好像正在吃什么东西。4) 完成进行式表示动作从过去开始并延续至说话的时候。例如:She is known to have been working on the problem for many years. 我们知道她研究这问题有好几年了。14. 动名词与不定式1)动名词与不定式的区别:动名词表达的是: 状态,性质,心境,抽象,经常性,已发生的不定式表达的是: 目的,结果,原因,具体,一次性,将发生的2)有些动词如continue接不定式或动名词作宾语,意义基本相同。3)有些动词如continue接不定式或动名词作宾语,意义大相径庭。常见的,下一节有专门
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