动词不定式的时态： 1.一般式所表示的动作或存在的状态发生在谓语动 词之后或同时发生。“to do”I consider him to be a good students.I want to finish my homework tomorrow. 2. 进行时所表示的动作和谓语动作所表示的动作同 时发生。“to be doing”He seems to be sleeping. 3.完成式所表示的动作和存在的状态发生在谓语动 词所表示的动作之前。“to have done”Im sorry to have kept you waiting for a long time.2.不定式的语态：当不定式的逻辑主语是 不定式的承受者时用被动语态“to be done/ to have been done”,反之，是主动 语态。e.g. The problem to be discussed next is important.The team seems to have been defeated,for they looks unhappy.To solve the problem,we discuss it for a long time. 3.不定式的用法： 1）做主语；eg.To be a good teacher is not easy.To see is to believe.(主语和表语同为 不定式时，不能用形式主语it代替不定 式) *不定式作主语时，为保持句子平衡可用 it作形式主语，把真正的主语放在后边 。eg.Its a pleasure to work with you.2)作宾语； a）一些及物动词必须加不定式作宾语，如： want,wish ,expect,would like,plan,agree,refuse,ask, decide,try,manage,pretende.g. She doesnt want to clean the house because she is busy. b)当不定式做宾语时，为了平衡句子结构，可以 用it做形式宾语. We find it difficult to understand his theory. We make it a habit to correct the mistakes in our homework.3)作表语；e.g. His dream is to be a success.He seems to have known the truth.4)作定语；放在被修饰的词之后,和所修饰的名 词构成动宾、主谓或同位关系。 e.g. Give me a piece of paper to write on.He found a hard chair to sit on.He engaged a nurse to look after his parents.I really want to have a chance to study abroad. *5)作状语；e.g. He came to see me yesterday. (表目的)He is too old to look after himself. (表结果) so as to 不位于句首； in order to 位于句中 ，句首。 b) (only ) to + v 表未曾预料的结果。e.g. He woke up only to find he was in hospital.In order to catch up with others,he works very hard every day.He works very hard every day, in order to/so as to catch up with others.*一些表示情绪色彩的形容词，如：glad, pleased, nice, ready, eager, afraid, sorry, willing, free后跟不定式做目的状语。e.g.She is afraid to be left home. *句子的主语是不定式的逻辑宾语，此时的不 定式必须是及物动词或及物短语，切用主动 形式。 常见的形容词有easy, difficult, cheap, expensive, dangerous, hard, comfortable The theory is easy to explain. The chair is comfortable to sit on.6)作宾语补足语； e.g.The teacher told the students to stand in line.The students were told to stand in the line. a)感官动词后，如：see,watch,look at,observe,notice,hear, listen to,feel 及使 役动词let,have,make等动词后，不定式 作宾语常省去“to”，但在被动语态中， 作主语补足语必须带“to”。e.g. I saw him go upstairs just now.He was seen to go upstairs just now .b)help后不定式作宾补“to”可有可无。e.g. Can you help me(to) solve the problem ? c)介词but ,except, besides后的宾语则采用“ 有do无to有to无do”的原则。 He had nothing to do but leave his hometown. He had no choice but to leave his hometown.4.不定式的否定：not to+ 动词原形*不定式否定式有时可用 never+不定式e.g. He promised me never to smoke again. 5.不定式的复合结构：1) for /of sb. to do sth.e.g. Its important for us to study a foreign language.Its very kind of you to help me. *用介词of还是for主要处决于句中adj，若adj 是表现人的品质、特征则用of，如： kind,polite,honest,careful,careless,etc;2)疑问词+不定式在句子中可做主语、宾语、 表语、定语 Last summer I took a course on how to make dresses. Whether to invite him to attend our celebration remains to be seen. 6.不定式的小品词to省略的情况 1）在使役动词或感官动词后做宾补时，且该 句为主动语态2）在介词but ,except, besides后做宾语时若介 词前出现了do的某种形式 Sandy could do nothing but_that he was wrong.(admit) 3)当含有do的定语从句来修饰的先行词all, the first/only/last thing或含do的主语从句充当复 合句的主语时，该复合句中的表语省去to What you should do now is make an apology to your guestMost fruits are naturally sweet and we eat them just the way they areall we have to do is clean or peel them The fist thing youd better do now is pay back the extra money to the customer.4.在一些固定词组如can but,cannot but,can not help but,can not choose but, but之后的不 定式省去to I cannot help but take the medicine I couldnt choose but stay at home 5. 在连接的不定式可采取承前省略的原则，但不 定式之间是对立相反含义时，则不可承前省略 The purpose of new technologies is to make life easier, - it more difficult A.not make B. not to male C. Not making D.do not make20. The library needs _,but itll have to wait until Sunday. A. cleaning B. be cleaned C. clean D. being cleaned1.He gave us some advice on how_ English.A.learning B. learned C. to learn D. learn2. It s a pay day，and they are waiting_.A. pay B. paying C. paid D. to be paid 3. - A letter may be too slow.- Why not _ a telegram.A.try sending B.try to send C.to try sending D.trying to send巩固练习CDA6. To master a foreign language,_.A. a lot of practice is needed B. it needs a lot of practiceC. practice is in need of D. one needs a lot of practice 5.Mrs.Smith warned her husband_ after drinking again and again.A.never to drive B.to never drive C.never driving D.never rive DA4.Our father often told us in the past that _is believing.A.to see B.seeing C.see D.to be seenB8.She will tell us why she feels so strongly that each of us has a role _in making the earth a better place to live. A.to have played; B.to play; C.to be played;