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课件网) 动词不定式是非谓语动词的一种，它没有人称和数的变化，在句子中不能独立作谓语，但它仍保持动词的特点，既可以有自己的宾语和状语。 用法 动词不定式具有名词、形容词和副词的特征。因此在句中可以做主语、表语、宾语、宾语补足语、定语和状语。 定义 基本形式 一般形式 to do not to do to be done 一般式表示的动作或状态，发生在谓语动词表示的动作或状态的同时或之后 否定形式 被动形式 完成形式 完成式表示动作或状态，发生在谓语动词表示的动作或状态之前 to have done 进行式表示的动作或状态，与谓语动词表示的动作或状态同时发生 to be doing 进行形式 1、不定式做主语一般表示具体的某次动作。 e.g: To finish the building in a month is difficult work. To do such things is foolish. 注: 1 不定式作主语时,谓语用单数 2、当主语较长，谓语较短时，常用it做形式主语，而将不定式放到谓语的后面。 一、不定式做主语： it做形式主语，不定式放在谓语动词之后常用于下列结构中： (1) It is/was +adj.+of sb. to do… 注意：在此句型中，adj. 只能用可以修饰 人物的形容词。 例如: kind nice good brave clever wise stupid foolish honest careless cruel generous eg: It is brave of him to save the girl in the water. It was careless of her to make such a mistake. (2) It is +adj.+for sb.+to do… 注意：这里的adj. 不能表示人的性质，只能表示某事或 某物的性质。 例如：difficult, wonderful, meaningful, painful, useful Eg: It is not difficult for us to learn English well. It is right for him to work here. (3) it is +a +名词+ to do Eg : What fun it is to jump into a lake in summer! How long did it take you to finish the work 例如: pleasure pity duty shame crime 等 注: 在感叹句和疑问句中只能用it作形式主语 Eg : It is a duty to plant trees every day . 不定式作表语常表示将来的动作 一、不定式做表语： eg : My idea is to climb the mountain from the north. Your mistake was not to write that letter. What I would suggest is to start work at once. 1.主语是以aim duty hope idea intention mistake plan proposal job suggestion wish purpose task 等为中心词的名词词组 或以 what 引导的名词性从 句表示，后面的不定式说明其内容 2主语和表语都是不定式（其含义往往一是条件，一是结果） Eg : To be kind to the enemy is to be cruel to the people. To do that would be to cut the foot to fit the shoe. 3 不定式常用在系动词 be, seem, appear, get, remain become , look , sound , taste , smell , feel , 等后作表语． All you have to do is (to )press the button. The only thing I can do is (to) give you as much help as I can. Eg : The plan seems to have been changed . 4 在某些句型中，当主语部分有动作动词do时，作表语的不定式可以省略符号 “to”，例如： 三 动词不定式作宾语 常用动词有: like wish hope want try begin start mean agree refuse promise pretend ask choose decide forget hope learn want would like intend demand expect fail offer help hate attempt determine try manage remember prepare plan 等 Eg : We hope to get there before dark. The girl decided to do it herself. 1、“动词 + 带 to 的不定式结构” 2 不定式即可作动词的宾语也可作介词的宾语. 不定式作介词的宾语时,介词之后一般不直接接不定式，一般都是:疑问词+不定式 ... ...
