不定式的用法.ppt

Grammar Infinitive 不定式 1. 构成及特征 动词不定式有两种形式： to + 动词原形 动词原形 动词不定式没有人称和数的变化，在句子中不能作谓语。 2. 动词不定式的时态和语态 不定式短语作主语常用it先行词作形式主语，而把不定式短语后置，以避免句子结构头重脚轻。 学会一门外语是不容易的。 It is not easy to learn a foreign language. 开快车是很危险的。 It is dangerous to drive very fast. It took a very long time to carve a page for a book. 刻一页书要花很长时间。 注：在it先行词作主语的句型中常用for sb或of sb作不定式的逻辑主语， 1.for sb句型中通常用表示客观情况的形容词。这样的形容词有： Easy, difficult, hard, important, possible, necessary, interesting等 2. of sb句型中一般用表示主观感情或态度的形容词。如： Good, kind, nice, wise, clever, foolish, right, wrong, careful, polite等 Exercise It is very kind you to help us. It is important us to express our opinions. It is difficult us to finish the work in such a short time. It is impolite him to say so. Like, want, try, wish, begin, decide, ask, forget, promise, offer, expect, agree, pretend, prepare, prefer, continue, mean 等 1. Fred 没有钱，所以他决定找一份工作。 Fred didn’t have any money, so he decided to look for a job. 2. 他答应不告述任何人这事。 He promised not to tell anyone about it. 作表语的不定式往往说明主语的内容。主语通常是： Hope, idea, job, plan, wish等(常在be, seem, remain, appear等动词后) 1. 我的工作是教英语。 My job is to teach English. 2. 眼见为实。 To see is to believe. 注：这种句型谓语动词变为被动结构时to不能省。 He heard someone come up the stair. 他听见有人上楼了. 听见有人上楼了 Someone was heard to come up the stairs. * 表示动作与谓语动词的动作同时发生 To be doing 进行式 表示动作发生在谓语动词的动作之前 To have been done To have done 完成式 一般情况或未来发生的动作或状态 To be done To do 一般式 基本用法 被动形式 主动形式 动词不定式的时态 1. I opened the door to enter the room. 2. Mr. Smith is going to attend the meeting to be held tomorrow. ㈠. 一般式( to do ). 一般情况或未来发生的动作或状态 ㈡.进行式( to be doing) 1. I am very glad to be working with you. 2. He is said to be coming. 表示动作与谓语动词的动作同时发生 动词不定式的时态 动词不定式的时态 ㈢.完成式（to have done) 1. I am sorry to have kept you waiting so long. 2. You seemed to have read the novel written by Mr. Smith. 表示动作发生在谓语动词的动作之前 动词不定式的语态 ㈠.主动式( to do / to be doing /to have done) 1. We want to learn English well. 2.Robert is said____abroad, but I d