1、Do you believe I used to be very thin?Its hard for you _ that now._ is to believe.To seeto believeHow can you believe?The infinitive不定式由不定式由“to+do(动词原形动词原形)”构成构成,其其否否定形式是定形式是“not to do”,不定式可以带宾语不定式可以带宾语或状语构成不定式短语或状语构成不定式短语,没有人称和数的没有人称和数的变化变化,但有时态和语态的变化但有时态和语态的变化。The definition of infinitive I am gla
2、d to see you.He has decided to give her some money.表示的动作通常与谓语所表示的动作表示的动作通常与谓语所表示的动作 或状态同时或者几乎同时发生，或是或状态同时或者几乎同时发生，或是 在它之后发生。在它之后发生。I am very glad to be working with you.He pretended to be working hardwhen his boss passed him.表示的动作通常与谓语动词表示的动表示的动作通常与谓语动词表示的动作同时发生。作同时发生。He happened to have seen the fi
3、lm before.The novel is believed to have been translated into Chinese.不定式所表示的动作发生在谓语动作不定式所表示的动作发生在谓语动作或状态之前。或状态之前。主动语态主动语态 to do 被动语态被动语态 to be doneIt is an honor for me to be invited to attend the meeting.Everyone likes the hero to be praised.1.主语主语(subject)2.表语表语(predicative)3.宾语宾语(object)4.宾补宾补(ob
4、ject complement)5.定语定语(attribute)6.状语状语(adverbial)7.独立结构独立结构(absolute construction)To keep smiling is healthy for you.单个不定式作主语时单个不定式作主语时,谓语动词用单数谓语动词用单数。Its important to look up the new words in the dictionary when you study English.若不定式太长若不定式太长,往往用往往用it作形式作形式主语主语,不定式后置。不定式后置。1.不定式作主语不定式作主语(subject)M
5、y job to protect the world.is2.不定式作表语不定式作表语(predicative)Seeing is to believe.To see is believing.To see is to believe.不定式常用在系动词不定式常用在系动词be,seem,appear,get,remain等后作表语。等后作表语。All you have to do is(to)finish the job quickly.如果主语部分含有如果主语部分含有do的某种形式的某种形式,用作用作表语的不定式可省略表语的不定式可省略to。A.表示按计划和安排将要发生的事情。表示按计划和安
6、排将要发生的事情。My job is to help the patient.B.表示主语的内容，表示主语的内容，但侧重于目的性。但侧重于目的性。Her wish was to become an artist.C.表示情态意义表示情态意义(应该应该,必须必须)。The form is to be filled in and returned within a week.小结：小结：Lin Shuhao likes to play basketball.I find it still necessary (for him)_ if he wants to win.句型：句型：think/con
7、sider/find/+it+adj.+to do to work hard某些动词后往往用某些动词后往往用it作形作形式宾语式宾语,不定式后置。不定式后置。3.不定式作宾语不定式作宾语(object)agree,afford,appear,ask,attempt,care,choose,claim,dare,decide,demand,deserve,determine,expect,fail,get,hate,hesitate,hope,hurry,intend,learn,manage,offer,plan,prepare,pretend,promise,refuse,seem,tend
8、,threaten,want,wish+to do常见动词不定式作宾语的动词有：常见动词不定式作宾语的动词有：sorry,surprised,happy,glad,eager,angry,foolish,right,wrong,slow,quick,rude,cruel,disappointede.g.Im glad/pleased to see you.We were surprised to hear the news.Look at the sentences and find the rules.不定式可以用在某些形容词后作宾语，不定式可以用在某些形容词后作宾语，如：如：My mum
9、asks me to play the piano two hours every day.4.不定式作宾补不定式作宾补(object complement)The teacher told me _ _.+sb.to do sth.warn,tell,allow,help,ask,force,expect to clean the blackboard引导不定式作宾补的动词引导不定式作宾补的动词 1.不定式在感官动词不定式在感官动词(feel,hear,listen to,watch,look at,notice,observe)后；后；2.使役动词使役动词(let,have,make)后。
10、后。不定式作宾补时不带不定式作宾补时不带to的情况的情况五看五看(watch,see,look at,notice,observe)三使三使(make,let,have)二听二听(listen to,hear)一感觉一感觉(feel)1.They saw the boy fall suddenly from the tree.The boy was seen to fall suddenly from the tree.2.Mother made John wash the car.John was made to wash the car.以上的动词用于被动式，以上的动词用于被动式，to 要
11、还原要还原1.It is looking for a suitable coat to wear.2.Tom has a nice pen to write with.5.不定式作定语不定式作定语(attribute)1.不定式作定语时常放在被修饰的名不定式作定语时常放在被修饰的名 词或代词之后。词或代词之后。(a)She was very busy and had no time to visit her friends.(b)Ladies and gentlemen,I have something important to tell you.2.当名词被当名词被the first,the
12、 last,the only 等词以及形容词最高级修饰时，后常等词以及形容词最高级修饰时，后常 用不定式作定语。用不定式作定语。e.g.She is always the first to come and the last to leave.3.something,anything,nothing,everything等复合不定代词常用不定等复合不定代词常用不定 式作后置定语。式作后置定语。I have something urgent to inform you.4.如果不定式是不及物动词如果不定式是不及物动词,则后面需加则后面需加 适当的介词。适当的介词。e.g.Please pass
13、me some paper to write _.on6.不定式作状语不定式作状语(adverbial)_(be)a winner,you need to give all you have and try your best.To beIn order to improve English,_.A.Jennys father bought her a lot of tapesB.Jenny bought a lot of tapes for herself 不定式作状语，其逻辑主语不定式作状语，其逻辑主语 通常是句子通常是句子的主语。的主语。不定式表示结果常见于下列句型不定式表示结果常见于下
14、列句型1)only to doHe lifted a rock only to drop it on his own feet.2)enough to doHe didnt run fast enough to catch the train.3)too.to doHis eyesight is too poor to read such small letters.4)so.as to doWould you be so kind as to lend me your bicycle?5)such.as to doWe are not such fools as to believe him
15、.(陕西陕西)If he takes on his work,he will have no choice but _(meet)an even greater challenge.解析：介词后一般只能接动名词，但在表介词后一般只能接动名词，但在表示示“除除外外”的介词的介词but和和except后，有后，有时可接不定式；当前面有行为动词时可接不定式；当前面有行为动词do时，时，不定式不带不定式不带to；前面没有行为动词；前面没有行为动词do时，时，要带要带to。to meet(2012 四川四川)Tom took a taxi to the airport,only _(find)his p
16、lane high up in the sky.to find(山东山东)George returned after the war,only _(tell)that his wife had left him.to be told辨析辨析 doing/to do 作结果状语作结果状语I went to see my aunt only to find her out.I went to see my aunt,finding her out.为了避免重复，常用to代替动词不定式.She wants to come，but her parents wont allow her toDont t
17、ouch anything unless your teacher tells you toTo tell the truth,I am not happy at the moment.to be frank to be honest to tell the truth7.独立结构独立结构(absolute construction)Practice:1.As a result of the serious flood,two-thirds of the buildings in the area need _(repair).2.Sandy could do nothing but _(ad
18、mit)to his teacher that he was wrong.3.Energy drinks are not allowed _(make)in Australia but are brought in from New Zealand.repairing/to be repairedadmitto be made4.My advisor encouraged me _(take)a summer course to improve my writing skills.5.My parents have always made me _(feel)good about myself
19、,even when I was twelve.to takefeel6.Paul doesnt have to be made _(learn).He always works hard.7.The director had her assistant _(pick)up some hot dogs for the meeting.8.Did Peter fix the computer himself?He had it _(fix),because he doesnt know much about computers.to learnpickfixed9.You were silly
20、not_(lock)your car.10.I like getting up very early in summer.The morning air is so good_(breathe).11._(complete)the project as planned,well have to work two more hours a day.to have lockedto breatheTo complete12.If theres a lot of work _(do),I am happy to just keep on until it is finished.13.-The la
21、st one _(arrive)pays the meal.Agreed!14.Due to the heavy rain and flooding,ten million people have been forced_(leave)their homesto doto arriveto leave15.Robert is said _(study)abroad,but I dont know what country he studies in.16.The question _(discuss)next year has something important to do with ou
22、r daily life.to have been studyingto be discussedstop to do sth.停下来去做某事停下来去做某事 doing sth.停止做某事停止做某事forget to do sth.忘记去做某事忘记去做某事 doing sth.忘记已做了某事忘记已做了某事remember to do sth.记得去做某事记得去做某事 doing sth.记得曾经做某事记得曾经做某事Something worth your attention e.g.The question is very difficult to answer.The problem is
23、difficult to deal with.1.主语主语+be+adj.+to do 能用于此句型的形容词有能用于此句型的形容词有:difficult,easy,comfortable,fit,hard,pleasant,tiresome(使人疲劳的使人疲劳的),interesting,nice,heavy,dangerous,light,important,etc.The box is light enough to carry.The river water is warm enough to swim in.2.主语主语+be+adj.+enough+to do The books seemed too heavy to carry.The ice is too thin to skate on.3.主语主语+be+too+adj.+to do
