The Infinitive 一、动词不定式的不同形式一、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动词不定式在句中作用 1.主语 To be a good teacher requires patience. It is important for 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 doeasy/difficult/hard/right/wrong/unnecessary(2)It is/was +adj. + (of sb.) to dokind/clever/foolish/strange/polite(3) It is +名词名词+ to do.a pity/an honor/ones duty/no easy job/good manners 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, threaten, wish 等) 辨析不定式与动名词： 1) 动词动词 remember, forget, regret 后接动名词表示已经做过的动作后接动名词表示已经做过的动作,不定式表示不定式表示 没有做过或将要做的动作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) 动词动词 like, love, hate, begin, start 既可用动名词也可用不定式作宾语既可用动名词也可用不定式作宾语,意思基意思基 本相同，但动名词表经常性的动作，不定式偏向一次性动作。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 to watch TV at home tonight.3) try to do / try doingmean to do / mean doingcant help to do / cant help doingstop to do / stop doinggo on to do / go on doingneed / want / require doing=to be doneThe door needs repairing. = The door needs to be repaired.3.宾语补足语 He told me to take care of the puppy 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 和和 there be 句型中，常用主动表被动。句型中，常用主动表被动。)Please give me a pen to write with.Please give me a piece of paper to write .5.状语 1) 目的状语目的状语: to do, so as to do, in order to do He 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：结果状语：only, enough to do, tooto do, soas (not) to Some 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 believe. 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动词不定式的注意事项 1. 疑问词不定式疑问词不定式,作主语、表语或宾语作主语、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 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 blame 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 rather，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.