第五讲 不定式.doc

不定式一 不定式概述1. 动词不定式与动名词、过去分词一样是动词的一种非谓语形式。2. 不定式的形式主动语态被动语态一般式to do to be done完成式to have doneto have been done进行式to be doing完成进行式to have been doing二 不定式做名词的用法1. 不定式做主语To see is to bilieve.To finish so much work in a day is impossible.It is one thing to know something about English and quite another to know English.当做主语的不定式短语（即不定式带有自己的宾语、状语或逻辑主语）较长时，常用it做形式主语，而将真正的主语放在谓语后。常见的带形式主语it的句型有：句型一It is easy/difficult/hard/impossible/hard/important/right/possible/necessary/unnecessary/foolish to do 句型二It is a pleasure/pity/pleasant thing/crime/an honour to do sth句型三It takes sb some time to do sth句型一中我们常用for sb或of sb来做不定式的逻辑上的主语，两者的区别在于： 两者使用的形容词不同for sb的句型通常使用表示客观情况的形容词，如：difficult, easy, hard, important, impossible, interesting, necessary, unnecessary, possible It is necessary for us to express our ideas.It is important for us to obey the rules.It is difficult for us to protect the environment,but we should try our best.of sb 的句型通常使用表示主观感情或态度的形容词，如：careful, clever, impolite, nice, polite, right, wise, wrongIt is clever of him to leave the country.It is polite of you to help the old. of sb 句型一般都可以换成一个不定式做状语的句子，而for sb 句型则不可以It is impolite for him to say so.He is impolite to say so.It is important for him to say so.He is important to say so.错误2. 做表语My wish is to be a doctor.Not to grasp firmly is not to grasp at all. 常见的动词：不定式做表语，一般紧跟在系动词如：seem, be, remain, appear, get等动词后，说明主语的内容What we have done to seems to harm the environment. 常见的主语：当我们用ones dream/wish/idea/plan/work/task/duty及what one wants to do 等做主语时，常用不定式做主语比较：句型一主语（事物）+be +不定式，表示主语的具体内容 句型一主语（人）+be +不定式，表示时态（将来时），即将He is to clean the room.His plan is to clean the room.3. 做宾语 不定式做动词宾语不定式用在及物动词后面充当宾语，常见的及物动词有：agree, aim, appear, arrange, ask, attempt, beg, choose, decide, demand, desire, expect, fail, happen, hope, manage, offer, plan, prepare, pretend, promise, prove, refuse, seem, want, wishHe decided to invite all his classmates to join in the party.The news proved to be true at last.I happened to meet my friend in the street, and asked her to have a cup of coffee with me.The workers refuse to work on weekends.Our boss promised to give us a raise.注：形式宾语：如果宾语有自己的表语，我们常常用it做形式宾语，而把真正的宾语放到后面，使用一下句型：主语+及物动词+it +宾语补足语+to+do常带有形式宾语的动词有：consider, believe, feel, make, find, know, regardWe think to obey the rule important.We think it important to obey the rule.I know it impossible to finish so much work in such a short time.We believe it necessary to protect the environment. 不定式做介词宾语不定式除了可以做及物动词的宾语外，还可以做but, expect, besides等介词的宾语。当介词but, expect, besides 前面是其他动词时，介词后接带to的不定式；而前面有实义动词do即其各种形式时，介词后面的不定式可以省去toexpect/but/besides + (to) do sthWhat do you like to do besides see a movie?We have no choice but to wait.除了but, expect, besides外，个别介词可以用“连接代词+（副词）+ 不定式”作宾语The boy has his own idea of how to finish it.三 不定式做形容词的用法不定式有时起形容词作用，用来修饰名词或代词，在句中做定语，通常放在名词或代词后面，做后置定语。做定语的不定式和中心词之间主要有如下关系：1. 同位关系吐过不定式是用来解释中心词的内容，那么它与中心词就是同位关系。常用的词有： need, wish, way, chance, opportunity, promise, attempt, ability, capacity, decision, determination, right, intention, eagerness, etc.He is famous for his ability to speak five languages.Studying abroad is an good opportunity to exchange culture.2. 主谓关系中心词可以看做是不定式的逻辑主语，说明中心词所处的状态或所做的动作；这类关系中，常常会由不定代词和序数词充当中心词。He is always the last one to leave the office.The next train to arrive was from Beijing.3. 动宾关系中心词是不定式的逻辑宾语。做定语的不定式有时是由“不及物动词+介词”构成，这事介词不可以省略，有时是由“及物动词+宾语+介词”构成，这时中心词是做介词的宾语，介词也不可省略。It was a game to remember.There is nothing to talk about.This is the bag to put these apples in.4. 动状关系中心词表示不定式发生的时间、地点、方式The children found a place to play.The couple was looking for a house to live in.四 不定式做副词的用法不定式在句中的作用有时和副词相同，在句中做状语，表示目的、原因、有时也表示结果，也可修饰形容词。1. 表原因 修饰表示感情的形容词常用的形容词和过去分词有：angry, anxious, clever, delighted, disappointed, eager, foolish, fortunate, frightened, glad, happy, lucky, pleased, proud, ready, sorry, willing, worthy, unfortunate, surprised, etc.He is surprised to hear the news.Liming was lucky to pass the exam.Our team were disappointed to lose the game. 修饰表示感情以外的词语下列形容词可用于这类结构中，且这类句子的主语可以是人，也可以是物，如：comfortable, difficult, easy, good, hard, pleasantThe house is very comfortable to live in.We found him very easy to get along with.2. 表目的I study hard to serve people well. 放在句首，加强语气To serve people well, I study very hard.To catch the bus, I get up early. 在不定式前加上in order to,或so as 加强语气In order to do the job well, I have to make a lot of preparation.I have to make a lot of preparation, so as to do the job well.3. 表结果不定式经常和only, never连用，强调结果和失望的情绪I hurried to get there only to find that all my classmates had gone.4. 其他用法 too + adj/adv + (for sb) to do sth (不定式在句中做结果状语)。too表示more than enough(过分)The book is too hard for the boy to read.We are never too old to learn.Too还可以表示十分，非常，极其，此时形容词一般用eager, anxiousThe students are too anxious to know the result of the exam.She is too happy to see her mother. 不定式用来修饰eboughHe is good enough to do the job.The room is large enough to hold the meeting. 不定式在句中做独立成分，如：to tell you the truth, to be fair, to be frank, to be sure, to make matters worseTo tell you the truth, I dont like the teacher.To be fair, it is not his fault.五 做宾语补足语不定式做宾补的情况很多，常用的动词有advise, allow, ask, beg, command, cause, expect, encourage, force, get, invite, instruct, like, order, oblige, persuade, permit, promise, request, tell, want, wish, remind, warnWe advise you not to go alone.My mothers reminded me to take an umbrella.to be 结构动词think, consider, find, believe, suppose, know, understand, take后，不定式做宾补时常用to beI consider him to be an honest man.The teacher thought the answer to be wrong.六 不定式的否定、连接（副）词+不定式1. 不定式的否定句型：not + to do, never to do2. 连接副词或代词+不定式不定式前面可以带一个连接代词或