Section Ⅲ Grammar——动词不定式
语 境 自 主 领 悟 先观察原句 1.Unfortunately，the doctors don't know how to make me better，but I am very outgoing and have learned to adapt to my disability. 2.Even after all that，no one could give my disease a name and it is difficult to know what the future holds. 3.I am happy to have found many things I can do，like writing and computer programming. 4.My ambition is to work for a firm that develops computer software when I grow up. 5.I have a very busy life with no time to sit around feeling sorry for myself. 后自主感悟 1.例句1中的how to make为“疑问词＋动词不定式”结构，作动词know的宾语；to adapt为动词不定式的一般式，作动词learn的宾语。 2.例句2中的不定式to know为真正的主语，前面的it为形式主语。 3.例句3中的to have found为不定式的完成式，作状语。 4.例句4中的不定式to work作表语。 5.例句5中的不定式to sit around作定语，不定式作定语位于所修饰的词之后。
动词不定式由“to＋动词原形”构成。这里的to是不定式标志，没有词义。不定式具有名词、形容词或副词的某些语法功能，又有动词的特点，可以有自己的宾语和状语，组成动词不定式短语。
一、动词不定式的形式 形式 一般式 主动语态 to do 被动语态 to be done to have been done 意义 表示动作与谓语动作同时发生或发生在谓语动作之后 表示动作发生在谓语动作之前 表示谓语动作发生时，不定式的动作正在进行 完成式 to have done 进行式 to be doing I plan to attend the meeting to be held tomorrow.
我打算参加明天举行的会议。(attend的动作在plan之后发生，且meeting与hold为被动关系)
They are said to be studying psychology. 据说他们正研究心理学。(be said与study同时发生)
I'm very sorry to have kept you sitting around doing nothing. 让你一直无所事事闲坐着我很抱歉。(keep发生在be sorry之前) No harm seems to have been done.
似乎并没有什么危害发生。(do发生在seem之前，且harm与do之间是被动关系) [名师点津]
(1)动词不定式的否定式
在不定式符号to前加not；不带to的不定式则在动词前加not。 Zhang Ming asked me not to stay at home all day. 张明要我不要整天待在家里。
My mother let me not do it by myself. 妈妈让我不要独自做这件事。 (2)“疑问词＋动词不定式”结构
疑问词“what，how，when，where，which＋动词不定式”结构可作主语、表语和宾语等。 He didn't know what to ask.(宾语) 他不知道该问些什么。
My question is when to start.(表语) 我的问题是何时开始。
[即时训练1] 用所给动词的适当形式填空
①They seem to have known(know) each other for a long time. ②They pretended to be working(work) hard when the teacher came in. ③I wanted the letter to be typed(type) at once. 二、不定式的句法功能
动词不定式在句中不能独立作谓语，但可以作主语、宾语、宾语补足语、定语、表语和状语等多种成分。
1．作主语
To talk with him is a great pleasure. 和他谈话是一件非常愉快的事。 [名师点津]
(1)为了避免头重脚轻，在许多情况下，通常都将作主语的不定式置于句子后部，用it作形式主语，放在句首。
(2)若要说明不定式的动作的执行者，可以在不定式前面加上“for/of＋n./pron.”结构。当形容词表达事物的特征时用for sb.；当形容词表达人所具有的特征或品质时用of sb.，这样的形容词有careful，cruel，foolish，brave，good，honest，kind，rude，polite，nice，stupid，wise，wrong等。
It's very important for you to remember this. 对你来说记住这一点很重要。 It's very kind of you to help me. 你能帮我真是太好了。 2．作表语
不定式作表语主要有三种情况，一是用于seem，appear，prove，turn out等连系动词之后的不定式(尤其是to be)；二是像My job is to sweep the floor(我的工作就是擦地板)这样的主语与表语“等价”的情形；三是表示想法、约定、义务、命令、可能性、命运等。
He seems to be ill. 他似乎有病。
Her wish is to be a teacher. 她的愿望就是当一名教师。
We are to meet at the station at three. 我们约定3点钟在车站见面。(表约定) 3．作宾语
常接不定式而不接动名词作宾语的动词及短语有：
“决心学会想希望”：decide/determine，learn，want，hope/wish/expect/long “设法假装在拒绝”：manage，pretend，refuse “主动答应选计划”：offer，promise，choose，plan “同意请求帮一帮”：agree，ask/beg，help 外加 afford，fail，would like/love，threaten。 I can't afford to buy a car.我买不起汽车。
I like swimming，but I don't like to swim this afternoon. 我喜欢游泳，但我今天下午不想游泳。 [名师点津]
不定式作宾语后跟宾语补足语时，常把不定式后移而用形式宾语 it 代替，常见句式：think/believe/consider/find/feel，etc.＋it＋adj./n.＋不定式。
I think it necessary to send for an expert. 我认为请位专家来是有必要的。 4．作宾语补足语
通常可带不定式作宾语补足语的动词：advise，allow，ask，bear，beg，cause，command，encourage，expect，forbid，force，get，hate，help，intend，invite，leave，like，mean，need，oblige，order，permit，persuade，prefer，request，remind，teach，tell，trouble，want，warn，wish等。
What caused him to change his mind? 是什么使他改变主意的？
He didn't allow the students to go there. 他不允许学生们去那儿。 5．作定语
I have a question to ask you. 我有一个问题要问你。
He is not a man to tell a lie. 他不是个说谎的人。 [名师点津]
不定式与被修饰的词有动宾关系，且句中有该不定式的逻辑主语时，该不定式用主动形式表被动意义。如果这个不定式是不及物动词，其后应有相应的介词。
The Browns have a comfortable house to live in. 布朗一家有一幢舒适的房子可以居住。 6．作状语
(1)动词不定式可以用作目的状语。注意其他非谓语动词形式不能用作目的状语。 To succeed，one must first of all believe in himself. 要想成功，首先必须相信自己。
(2)only to do sth.为不定式作结果状语，表示出乎意料的结果。
We hurried to the station，only to be told that the train had left. 我们急匆匆赶到车站，结果被告知火车已开走了。
(3)形容词或过去分词作表语时，后面可接不定式作原因状语。常见词有：happy，lucky，glad，sorry，anxious，proud，disappointed，angry，surprised，ready，delighted，clever，foolish，pleased，fortunate，right等。
You will never know how happy I was to see her yesterday. 你永远不会知道昨天看到她时，我是多么高兴。
(4)在“主语＋系动词＋表语(形容词) ＋to do”结构中，不定式的主动形式表示被动意义。该结构中常用的形容词有：easy，hard，difficult，important，impossible，interesting，pleasant，nice，comfortable，safe，dangerous等。
The box is not easy to carry.
这个箱子不易携带。
7．动词不定式与疑问词who，which，when，where，how，what等连用，在句中起名词的作用，可充当主语、表语、宾语等。
How to solve the problem is very important. 如何解决那个问题很重要。(作主语) [即时训练2] 用所给动词的适当形式填空
①It took years of work to reduce (reduce) the industrial pollution and clean the water.
②I heard a passenger behind me shouting to the driver，but he refused to stop (stop) until we reached the next stop.
③He is thought to have acted (act) foolishly.Now he has no one but himself to blame for losing the job.
三、省略to的情况
1．在某些使役动词或感官动词后作宾语补足语的动词不定式，常不带to；如果这些动词用于被动结构，其后的to就必须补上。这类词可以用以下口诀助记：
一感：feel 二听：listen to，hear 三让：make，have，let 五看：see，watch，observe，look at，notice。 I often hear him sing the song. 我经常听见他唱那首歌。
He is often heard to sing the song. 他经常被人听见唱那首歌。
2．在以why引导的疑问句中，表示建议，不定式不带to。 Why congratulate her? 为什么要祝贺她呢？
Why not conduct the interview right now? 为什么不马上主持面试呢？
3．在cannot but，cannot choose but，cannot help but之后的动词不定式不带to。 I cannot but admire his courage. 我只有佩服他的勇气。
4．动词不定式在but，except，besides后面时，如果这些词之前有行为动词do，那么，这些词后的动词不定式不带to，否则要带to。
She could do nothing but cry. 她除了哭，不能做任何事。
I have no choice but to work for the firm.
相关推荐：
loading