三个好朋友英语故事:初中英语动词不定式精讲

初中英语动词不定式精讲

动词不定式是由“不定式符号to (另外一个名称叫小品词to+动词原形”)构成的一种非谓语动词结构。有些动词不定式不带to，即只有动词原形，这种情况更需特别注意。动词不定式可以作句子的主语、表语、宾语、定语、补语、状语或单独使用。不定式保留动词的某些特性，即可以有自己的宾语、状语等。动词不定式和它后面的宾语、状语等其他成分一起构成短语，叫作不定式短语现对初中教材动词不定式的用法作一简要梳理，供初中毕业班教师和学生在学习和复习时使用。
一、动词不定式用作主语
动词不定式用作主语，顾名思义，就是句子的主语用动词不定式充当。
直接把动词不定式置于句首作主语的情况并不多，多数情况用it作形式主语，把真正的主语——动词不定式置于句末，特别是不定式短语较长、较复杂时。动词不定式作主语，谓语动词用第三人称单数形式。不定式短语和疑问词连用作主语，常置于句首；复合不定式结构作主语常置于句末。如：
1. It is our duty to keep our classroom clean and tidy every day.
分析：It为形式主语，真正主语为后面不定式结构：to keep our classroom clean and tidy every day.
2. It is not hard for me to learn English well.
分析：真正主语为to learn English well。为使句子保持平衡，用it放到前面，作句子句法功能意义上的主语，即形式主语。for me 是动词不定式逻辑上是主语。
3. Whether to tell this to his father or not is a difficult question.
分析：不定式结构to tell this to his father or not 和疑问词whether 一块做句子主语。这种情况，注意后面谓语动词用单数形式。例如本句用了is。
对不定式作主语掌握的要求，初中教材不需太深，理解两个词语：真正主语、形式主语。掌握一个结构：It is(was)+形容词/名词（for sb.）+to do sth.注意一个句式：不定式短语和疑问词连用作主语，常置于句首，后面谓语用单数。
高层次的要求让学生理解动词不定式和动名词作主语的区别。一般而言，在表示比较抽象的一般行为时多采用动名词；在表示具体的某次动作，特别是将来动作时多用不定式。例：Smoking is bad for your health./ It is not good for you to smoke so much.
二、用作表语
动词不定式作表语，也就是be动词后作表语成分由不定式结构充当。
动词不定式作表语，常说明主语的内容、性质、特征。如：
1. The best way to improve your English is to use English every day.
2. The important thing is to finish your homework first.
动词不定式作表语，在初中教材是学生掌握理解的难点。学生在判断用动词不定式还是用动名词作表语，往往难以入手。突破要点：理解上面动词不定和动名词作主语区别，动词不定式和动名词作表语区别一样。(一般而言，在表示比较抽象的一般行为时多采用动名词；在表示具体的某次动作，特别是将来动作时多用不定式。)例：My job is teaching./ My task now is to teach you to look out the problem.
三、用作宾语
动词不定式作宾语，就是放在动词后或介词后作宾语的成分由不定式结构来担当。
1.可以接带to的动词不定式作宾语的动词主要有：想要记住忘记(want, would like, remember, forget)；需要努力学习(need, try, learn)；喜欢同意帮助( like, love, agree, help)；希望决定开始(hope, wish, decide, begin, start)
1) We decided to have a picnic this weekend.
2) He is trying to improve his study.
3) I would love to visit Mexico.
2. 不定式结构和疑问词连用，可以一起作前面动词或介词的宾语。这类动词有decide, know, learn, show, teach, tell等。如：
1) Could you please tell me how to get to the hospital?
2) They are talking about where to spend their holiday.
3. 动词feel, find, make, think等后面，可以用it作形式宾语代替真正的宾语——动词不定式，句子结构是...feel / find / make / ..+ it + adj. / n+to do...。如：
I find it difficult to learn English well.
We feel it our duty to keep our classroom clean.
4.有些动词后既可接动词不定式又可接v-ing形式作宾语。两者之间意思差别不大的动词有begin, start, like, love等。非要严格界定两者区别，一般说来，动词不定式表示具体的偶尔的某次动作、将来动作或动作的全过程，v-ing形式表习惯性的连续动作或概括性抽象性动作。如
1) I started to watch TV when I got home. /I started learning English at the age of eight. I
2) Do you like playing football? Do you like to play football with me this afternoon?
5. 后接动词不定式或v-ing形式作宾语，意思差别较大的动词有forget, remember, stop等。后接不定式作宾语，表动作尚未发生,将去做；后接v-ing形式作宾语，表动作已经发生，强调这件事情本身。如：
1) I forgot to do my homework last night. (昨晚我忘记去做作业了)
I forgot telling him the story before. So when I told him the story again, he laughed. (我忘记我以前给他讲过这个故事了。因此当我再给他讲时，他笑了。)
2) --Lucy, have you cleaned your bedroom? If not, remember to clean it. –Yes, I remembered cleaning it this morning. (--露西，你打扫你的卧室了吗？如果没有，记住打扫。--是的，我记得今早上打扫了。)
3) Stop talking. I know we are very tired .OK, let’s stop to have a rest. (不要说了，我这到大家累了，那么，让我们停下歇会吧。
类似的try to do尽力做，try doing试试看；go on to do接着做另外的事，go on doing继续做原来的事。
四、用作定语
动词不定式作定语，因其结构比较长，常放在所修饰的名词后作后置定语。
1) I have so much homework to do today.
2) I can’t think of any good advice to give her.
3) Basketball has also become a more popular sport for people to watch.
4) I have no time to have breakfast.
5) Can you tell me the best way to learn English?
6) There’s so much to see and do here.
五、用作补语
动词不定式作补语时，在主动语态句里补宾语，在被动语态句里补主语，句子的宾语或主语是不定式动作的逻辑执行者。如果不定式是to be done，句子的宾语或主语就是逻辑承受者。
1. 在主、被动语态句里用带to的动词不定式作补语的动词主要有：要求允许提议(ask, allow, permit, advise)，期望邀请鼓励(expect, suppose, invite, encourage)，教导告诉想要(teach, tell, want)，等待希望愿意(wait for, wish, would like / love)。如：
1) I invited her to have dinner at my house yesterday.
2) Teenagers should be allowed to choose their own clothes.
3) Email English is supposed to be used on mobile phones.
2. 动词不定式作补语，在主动语态句里不带to，被动语态句里带to时多数动词是感官动词和使役动词，包括四“看”：look at, observe, see, watch，三“让”：have, let, make，二“听”：hear, listen to，一“感觉”：feel，一“注意”：notice。
如：1) His words made me feel very angry.
2) We often see the boy play football on the playground.
3. help后接动词不定式作补语，在主动语态里to可带可不带,在被动语态里，必须带出to来。
1) I often help my mum do the housework at home.
2) I am often helped to finish my homework with the help of my computer.
4. be said, be sure, happen, seem等后面可以接带to的动词不定式作主语的补语。如：
1) He doesn’t seem to have many friends.
2) Be sure not to miss them if they come to a city near you.

六、用作状语
1. 目的状语，置于句首或句末，置于句首时常表示强调。如：
1) In order not to offend people, learning about language etiquette is just as important as learning grammar or vocabulary.
2) A group of young people got together to(in order to / so as to) discuss this question.
to do / in order to do / so as to do用作目的状语，置句末时都可以用，置句首时只用to do / in order to do。so as to do一般不置于句首，可以引导结果状语从句，in order to do不引导结果状语从句。
2.原因状语，多见于“sb.+be+adj.+to do...”结构句中。如：
1) My dogs name is “Lucky”—a good name for him because I feel very lucky to have him.
2) On Monday he told a radio interviewer that he had run out of money to buy old bikes.
3.结果状语，多见于“too...to”，“enough to...”结构句中。如：
1) Then I’m too tired to do well. What should I do?
2) The room needs to be big enough for three people to live in.
4. 有些动词不定式作状语，常说明前面形容词的性质和特性。动词不定式与句子的主语有逻辑的动宾关系。动词不定式前面的形容词一般是：cheap, dangerous, difficult, easy, fun, hard, interesting, necessary。不定式常用主动式表被动意义。... the mistakes you made are necessary for you to learn and understand. 这类句子中的动词不定式可改为主语。
5. 独立动词不定式多用作插入语，表示说话人的心理状态或对事情的看法。如：
1) Id like to stay healthy, but to be honest, I only eat food that tastes good.
2) To begin with, she spoke too quickly, and I couldn’t understand every word.
七、动词不定式的复合结构
动词不定式的复合结构是“for / of sb. to do sth.”，for / of引出不定式动作的逻辑主语。这种结构在句子中可以作主语、宾语、表语、定语、状语等。不定式复合结构的介词用for还是of，主要决定于前面形容词的性质。一般说来，of前面的形容词是careful, clever, foolish, good, kind, nice, wise等，既说明人的特性，又说明不定式动作的特性。for前面的形容词是dangerous, difficult, easy, hard, heavy, important, interesting, necessary等，一般说明不定式动作的特性，不说明人的特性。前面如果是名词用for。如：
1. Its also probably a good idea for parents to allow teenagers to study in groups during the evening.
2. Zoos are terrible places for animals to live.
八、带疑问词的不定式短语
动词不定式前面可以带疑问代词what, which, who或疑问副词how, when, where, why等。这种结构起名词的作用，在句子里用作宾语、主语、表语等，或者单独使用。要注意的是，why后面的不定式不带to。如：
1. 用作句子的成分。
1) I don’t know what to try next. (作宾语)
2) Where to go is not decided yet.(作主语)
2. 单独使用时相当于一个特殊疑问句。
1) What to do next? (=What will we / you do next?)
2) Why go there? (=Why do we / you go there?)
九、动词不定式的否定式
不定式的否定式是not / never to do...，不带to的不定式的否定式是not / never do...如：
1. Sometimes they have disagreements, and decide not to talk to each other.(p.8)
2. His parents tell him never to drive after drinking.