非谓语动词动词不定式动词不定式是一种非谓语动词，由不定式符号to加原形动词构成，动词不定式保留着动词的一些特征：(1)带宾语或表语。例如：I want to watch TV.I hope to be an outstanding student.(2)可由状语修饰。例如： I expect you to study hard.(3)有时态和语态的变化。例如：Im sorry to have kept you waiting.（完成时）The questions to be answered are on page 10.（被动式） 动词不定式和它的宾语，状语，或表语一起构成不定式短语。不定式或不定式短语具有名词，形容词，和副词的性质，因而可以在句中作主语，宾语，表语，定语，和状语。在不定式符号to前加上not构成不定式的否定式。例如：He told me not to touch the wire.I. 动词不定式的句法作用1.作主语To master a foreign language is very important.Not to smoke will do you a lot of good.To obey the laws is everyones duty.动词不定式作主语时，常常用先行词it作形式主语，放在句首，将不定式移到谓语之后作实际主语。例如：It is difficult to answer such a complicated question in English.It has been possible to send man to space.It takes the electronic computer only a few seconds to solve the problem.Example:_ only five minutes to finish the task.a. It took myself b. It required me c. It should be needing d. It took me2.作表语Our main task is to carry these building materials to the work site.The most common way of getting heat is to burn fuel.Our goal is to accomplish the modernization of agriculture, industry, national defence, and science and technology.Example:My job _ these children.a. was to look after b. was looking c. is to looking after d. has looked after3作宾语在及物动词begin, cease, choose, continue, decide, expect, fail, forget, happen, hate, help, hope, intend, like, love, manage, mean, offer, plan, prefer, prepare, promise, refuse, remember, try, want, wish 等后边常用不定式作宾语。例如：When did you begin to learn English?Once you turn off the switch, electricity ceases to flow.He promised to keep the secret for you.Example:Galieo planned to _ the problem, but failed to do so.a. solving b. have solved c. be solved d. have been solvedIf you promise _ angry with me, Ill tell you what I broke.a. get not b. not get c. not to get d. not getting注意：当不定式作直接宾语，它后面还有宾语补足语时，需用it 作形式宾语代替不定式，而把不定式放在补足语之后。例如：I found it difficult to identify mistakes. 我发现辨认错误很难。Do you consider it wise to ignore him? 你认为不理睬他是明智的吗？Example:I found _ to answer all the questions within the time given.a. no possibility b. there was impossibility c. impossible d. it impossible动词不定式也可作介词but, except, save（除.以外）的宾语，但在词组can not but （不由得，只好）, cannot help but（不得不）, do nothing but（别无它法只有.）后面，接不带 to 的不定式。在except, save 后可带to也可不带 to。例如：The National Guardsmen were given no choice but to shoot over the heads of the unruly mob.She does nothing but cry all day.We cannot but believe in the youth who is always trying to improve himself.He did nothing except play all day long.There is nothing for it but to wait for an opportunity.Example:He was no alternative but _ to see him.a. go b. went c. going d. to go I _ at our teachers remarks.a. cannot but wonder b. cannot help but to wonder c. cannot but wondering d. cannot help but wondering4作宾语补足语有些动词如allow, advise, ask, beg, believe, cant bear, call, choose, cause, command, determine, enable, expect, fail, feel, find, force, get, have, hear, help, know, invite, lead, let, like, make, notice, order, prove, request, set, see, teach, tell, think, want, warn, watch, wish等后面常跟动词不定式作宾语补足语。注意：在make（使）, let（让）, have（使，叫）等使役动词后；在see（看）, watch （观看）, look at（看）, behold（看）, observe（观察，看见）, perceive（看见）, feel（感觉）, hear（听）, listen to （听.）, notice（发现，注意）等表示感官的动词后及在know（了解）, please（请）等后面省去动词不定式符号“to”。在动词find与 help 之后的“to”可省也不可省。例如：I asked him to tell me the results of the scientific research.Can you help me (to) clean the windows?Ask her to wait for me at the gate.Her mother never has her do that heavy work.Example:Professor Black had us _ compositions every Friday.a. to write b. written c. write d. wroteMy boss asked me to answer the phone, to take all messages, and _ some letters.a. to type b. typing c. type d. typewriteMy teacher told me _ so careless.a. not be b. dont to be c. not to be d. wont be有些动词如consider, prove, think, know, feel, suppose, discover, imagine, find 等也可跟“宾语 + to be”的形式，使用中应注意。例如：We found him (to be ) dishonest. 我们发现他不诚实。We all know him to be dead. 我们都以为他死了。Example:We _ Mr. Brown to be a fine writer.a. accept b. receive c. think d. regard5作主语补足语如果把动词不定式作宾语补足语的句中的谓语由主动语态改为被动语态，则宾语补足语就成了主语补足语。要注意作宾语补足语时在某些动词后省去的不定式符号to, 此时一般不能省去。例如：Plastics are found to be good insulators.Water power can be made to produce electricity.The laboring people of the world are called on to unite.号召全世界的劳动人民团结起来。Example:Children should be allowed _ their own decisions.a. making b. to make c. make d. having made6.作定语My father didnt have any chance to go to school before liberation.Energy is the ability to do work.Please give me something to drink.Example:The order _ pumps will come from the control room.a. stopping b. to stop c. stopped d