1、The Infinitive一、动词不定式的不同形式主动形式被动形式否定形式基本式to doto be donenot to do/ not to be done进行式 to be doingnot to be doing完成式 to have doneto have been donenot to have dong/not to have been done完成进行式to have been doingnot to have been doing三、动词不定式在句中作用1. 主语To be a good teacher requires patience.It is important f
2、or you to use your time wisely.It is brave of him to dive from the cliff.it 形式主语 (1)It is +adj.+ (for sb.) to do easy/difficult/hard/right/wrong/unnecessary (2)It is/was +adj. + (of sb.) to do kind/clever/foolish/strange/polite (3) It is +名词+ to do. a pity/an honor/ones duty/no easy job/good manners
3、 2. 宾语We hope to have more opportunities to talk with native speakers.They asked her how to get to the railway station.(常以不定式作宾语的动词：afford, agree, ask, attempt, beg, bother, care, choose, claim, decide, desire, expect, fail, help, intend, learn, manage, offer, plan, prepare, pretend, refuse, threate
4、n, wish等)辨析不定式与动名词：1) 动词remember, forget, regret后接动名词表示已经做过的动作,不定式表示没有做过或将要做的动作. I remember seeing him yesterday. I remember having seen him before. Please remember to see him today. 2) 动词like, love, hate, begin, start既可用动名词也可用不定式作宾语,意思基本相同，但动名词表经常性的动作，不定式偏向一次性动作。 I like watching TV at home. I like
5、to watch TV at home tonight.3) try to do / try doing mean to do / mean doing cant help to do / cant help doing stop to do / stop doing go on to do / go on doingneed / want / require doing=to be done The door needs repairing. = The door needs to be repaired.3. 宾语补足语He told me to take care of the pupp
6、y while he was away.My boss told me to sit there.（常见动词：advise, allow, ask, beg, encourage, expect, force, invite, order, permit, persuade, press, remind, teach, tell）4. 定语The building to be built is our library.We have a lot of things to do today.There are a lot of things to do.( have和there be句型中，常用
7、主动表被动。) Please give me a pen to write with. Please give me a piece of paper to write .5. 状语1) 目的状语: to do, so as to do, in order to doHe hid himself behind the door so that he couldnt be found by others.=He hid himself behind the door so as not to be found by others.2) 结果状语：only, enough to do, tooto
8、 do, soas (not) toSome people laugh at others, only to find themselves laughed at. She is so weak that she can not run fast. =She is so weak as not to run fast.She isnt strong enough to run fast.She is too weak to run fast. The question is easy .(answer) He is difficult .(teach)6. 表语To see is to bel
9、ieve. He is to visit China next week. 主要的任务是保持我们的寝室干净。The main task is to keep our dormitory clean.四、动词不定式的注意事项1. 疑问词不定式,作主语、表语或宾语1）what / which to do (what / which 作do 的逻辑宾语，what意为“什么”，which “表示选择”There were too many books for me to choose from and I didnt know which to choose.2）when / where / how
10、to do sth.I felt totally confused, not knowing where to go.3）whether to do sth. (不用if)Whether to follow his instruction is not for you to decide.2. 不定式的主动表被动 句中存在名词或代词可以作为不定式的逻辑主语，构成逻辑上的主谓关系。eg. Mrs Bird gave the dog a few bones to eat.The policeman showed me the right bus to take.如果句中不存在这种主谓关系，那么不定
11、式仍须用被动。eg. The news reporter raised a few questions to be answered. 在“形容词+不定式”结构中，如果不定式与句子主语构成逻辑上的动宾关系，那么不定式多用主动语态。eg.The plane is dangerous to fly.The machine is hard to control. There be结构中，倾向于用不定式主动语态表示被动意义。eg. There is always much housework to do in the house. blame, let在此为主动表被动。He is not to bla
12、me for the mistake.(他不应该为这个错误受责备。)The house is to let. (房子待租。)2. 不定式的省略 感官动词和使役动词在主动语态中不需要带to，即我们常说的“一觉二听三让五看” :feel, listen to, hear, let, make, have, see, watch, notice, observe, look at. 但这些句子如果变成被动结构时，就必须带to。I often hear him sing the song. He is often heard to sing the song. had better，would rat
13、her，rather than之后省略to。Youd better not tell him the news .Rather than wait at the station, I prefer to go home by taxi. 为避免重复，不定式中主要动词可省略，只剩下to。Would you like to come with us? - Yes, Id love to.Shall I give the dog a chocolate? -Its better not to. 由 all， what 引导的主语从句或主语被only, first, one, least 或形容词最高
14、级修饰，且从句中含有do时，动词不定式作表语则往往省去to。All I did was (to) press the button.What you have to do is (to) fill in the forms.The only thing I could do was (to) do it myself 。3. 和不定式有关的常用词组和句型 be said to doHe is said to have studied abroad for many years. happen to doWe happened to discover we had a friend in common. = It happened that we discovered that we had a friend in common. seem to doHe seemed to be looking for something. = It seemed that he was looking for something.