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1、动词不定式用法小结,动词不定式是一种非谓语动词形式，其结构为“to动词原形”，其中to不是介词，而是动词不定式的符号，称为小品词，动词不定式没有人称和数的变化。动词不定式和其后面的名词等构成不定式短语，在句子中可以用作主语、表语、宾语、补足语、定语、状语等。,一.作主语：,To look after my pets properly takes a lot of time.,To be a doctor is hard.To learn English well is not easy.,动词不定式短语作主语时，为了避免句子的头重脚轻，可以用“it”作形式主语，而把真正的主语动词不定式短语放在
2、句子的后部。例如上面的句子可以表示为：It is hard to be a doctor.It is not easy to learn English well.再如：Its important to plant trees in spring.,如果表示动词不定式的动作执行者，可以在不定式前面加一个由介词for引导的短语，称为不定式的复合结构。例：Its good for us to read English aloud in the morning.It is important for students to use English every day.,My ambition is
3、to work for firm that develops computer software when I grow up.,二.作表语：动词不定式（短语）作表语常用于系词be的后面。例：His work is to drive a car.My job is to feed animals.Her ambition is to be a doctor.,He hopes to become a teacher.,三.作宾语 动词不定式（短语）可以放在一些动词后面用作宾语，能以动词不定式作宾语的动词有：begin,start,want,forget,remember,show,learn,
4、like,hate,love,ask等。例：I want to tell you a story.They begin to work at eight every morning.Dont forget to lock the door.Would you like to go and have a picnic with us tomorrow?,注意：（1）如果and连接两个动词不定式，第二个动词不定式一般省“to”例：He wants to go and have a swim with us.（2）若作宾语的动词不定式（短语）很长，可用it作形式宾语。I find it intere
5、sting to learn English with you.He found it hard to catch up with others.,The teacher advised him to try another way.,四.作宾语补足语。例如：The teacher asked us to read English for half an hour in the morning.The teacher often tells Jim not to spend too much time playing computer games.Please let me help you.
6、动词不定式作宾语补足语，表示宾语所做的动作，可以用动词不定式作宾语补足语的动词有：tell,ask,want,like,invite,encourage,help等。但在let,make,see,watch,hear,feel,notice,have等感官听觉动词或使役动词后面作宾语补足语的动词不定式一般要省略动词不定式符号“to”，可以归纳为以下三种句式：,1.不可以省to的不定式作宾语补足语：tell/ask/want/would like/wish/like/invite/encourage/teach sb.to do sth.例：The teacher told us to come
7、 earlier tomorrow.I want you to go now.Her parents wish her to be a teacher.2.省“to”的不定式作宾语补足语：Let/make/have sb.do sth.Let the boy go out now.The boy made the baby cry.see/watch/hear/notice/feel sb.do sth.I saw the students play basketball on the playground yesterday.I often hear the girl sing in the
8、 next room.3.可省可不省的：help sb.（to）do sth.I often help my mother（to）do housework.,否定形式：（1）动词不定式的否定式是直接在to之前加not.例：Tell them not to play football in the street.（2）省to的动词不定式的否定式是直接在动词前面加not.例：Let the boy not go.被动语态：如果将主动语态变为被动语态时，作宾语补足语的动词不定式变为主语补足语，动词不定式则不省“to”，即原来省的再加上，例：The boy made the baby cry.The
9、baby was made to cry by the boy.,He has a good way to make his classes lively and interesting.,五.动词不定式作定语 动词不定式作定语常用来修饰名词或不定代词，放于所修饰的词后，为后置定语。例：Who was the first one to arrive?She has no paper to write on?The best way to learn English is to use it.When is the best time to plant vegetables?Do you hav
10、e something to drink?*动词不定式（短语）作定语修饰名词时，与其所修饰的词具有一种动宾关系，如果不定式中的动词为不及物动词时，其后应加上一个含义上所需要的介词。例：I have no chair to sit on.He has no house to live in.,Sometimes too,I was too weak to go to school.,六.作状语:动词不定式及其短语具有副词的特性，可在句中作状语。（1）作目的状语。如：He stopped to have a rest.（2）作结果状语。如：He woke up to find everybody
11、gone.（3）在某些表示喜、怒、哀、乐等的形容词后作原因状语。如：Im sorry to hear your grandma is ill.（4）在带有enough或too的句子里作状语，表程度。如：He is old enough to go to school.（5）强调动词不定式所表示的目的时，动词不定式可用in order to或so as to+动词原形，so as to不用于句首。如：The bus stopped so as to pick up passengers.,Wh+to do,七.不定式和疑问词连用，可以作句子的主语、宾语、表语等。例：The problem is
12、where to get a computer.（表语）No one knows how to do it.（宾）I really dont know which one to choose.（宾）When and where to have the party is not known.(主)*不定式和疑问词连用作宾语时有时可以改为宾语从句。例：I dont know what to do next.I dont know what I should do next.,练习：,Please tell him _ on the wall.A.dont drawB.to not drawC.no
13、t to drawD.not drawId like _ a word with you.A.had B.having C.to have D.have We often heard him _ in his room.A.to sing B.sings C.sang D.sing He was made _ day and night.A.work B.working C.to work D.workedHe stopped _ a look,but saw nothing.A.having B.to have C.have D.hadHe said he had an important
14、meeting _.A.attendB.would attendC.attendingD.to attend,Please give me a piece of paper _.A.to write B.to write on C.writing D.to write itI dont know _.A.what doB.what will do C.what to do D.do whatYour radio needs _.A.to be repairedB.to repair C.repaired D.to repairingPlease tell me _ her.I have something _ her.A.where to find,telling B.where to find,to tell C.where can find,to tellD.where finding,tellingHow happy they are _ each other again!A.to see B.see C.saw D.being seenThey decided _ a letter _ their thanks.A.to write,expressing B.writing,express C.write,expressed D.to write,to express,
