To do,一、动词不定式的作用,动词不定式具有副词、形容词和名词的特征，因此在句中可作主语、定语、宾语、表语、宾语补足语、状语等成分。,1.主语 To live is to work. To save time is to lengthen life. 但为使句子平衡,常用it 代它作主语, 把它移到句子后部去. It is a great pleasure to play basketball. 即:It is /was +adj/n+to do It is best to do so.,2.作表语 His job is to teach English. The main thing is to keep our machine from rust. A.表示按计划和安排将要发生的事情。 He is to marry Rose. B.表示主语的内容，但侧重于目的性。 Her wish was to become an artist. C. 表示情态意义(应该, 必须)。 The form is to be filled in and returned within a week. She is to blame.,3.作宾语（跟在某些动词后） I learn to speak English. They decided to begin the expriment at once. A. 跟不定式作宾语的常见动词: （）hope, want , expect, wish, desire, like, love, dislike ,hate, plan, intend, mean, prepare, decide, determine, afford, fail, manage, try、dare, help , promise、refuse、 learn、offer、 agree、forget ,bother ask beg decide seem preten wish demand refuse manage happen .,B. 常跟疑问词+不定式作宾语的动词: tell, advise, show, teach, find out, decide, discuss, learn, explain tell sb what to do,4作宾语补足语 I like you to do it this way. Please ask John to turn on the light. 跟不定式作宾语补足语的动词 A. let, have, make, get等表使役的动词 They made us go with them. 注意: Let/ have/make sb. do ; get sb. to do They got us to go with them. 注意：变被动式要加to The boy was made to study.,B. ask, tell, request, order等表要求,命令的动词 The chairman requested the members to be silent. C. allow, permit, forbid等表许可或禁止的动词 The guard forbade me to enter. D. wish, want, expect, intend等表希望的动词(hope无此用法) Many parents expect their children to study abroad E. see、watch、notice、hear、listen to、observe、feel等表感官的动词 I noticed tears come into his eyes. We often hear her sing the song at home. 注: 感官动词后的不定式均不带to,F. 其他动词 advise, help, persuade, encourage, warn, cause, force, remind Please remind me to take the raincoat.,5.作定语 （1）动词不定式作定语时，须放在被修饰的名词或代词的后面。 He said he had an important to attend. The fisherman had nothing to take home that moring. (2)如果不定式是不及物动词，后面就应有必要的介词。 Give me a piece of paper to write on. He is looking for a room to live in.,(3)有很多名词常可用不定式作定语。 Decision ,wish, chance, promise, plan,time,attempt ,effort ,right,ability, patience He had no chance to go to school. Tom had no time to think about rest. Is that the best way to solve the problem?,