1非谓语动词动词不定式、动名词和分词（现在分词、过去分词）统称为非谓语动词现代英语将现在分词和动名词合为一大类叫作 v + ing 形式这些动词的形式不能在句中单独作谓语用，因而没有语法主语但可以有逻辑主语由于没有语法主语，也就不受人称和数的限定，因为不是谓语，也就没有时态和语态，但这些词仍能表示动作和状态，所以仍有表示与其他动词相对时间关系的形式由于与其它词有逻辑上的主谓关系，因此也有表示主、被动的形式，同时也有自己的宾语和状语，一起构成非谓语动词的短语（动词不定式短语、分词短语、动名词短语） 非谓语动词在英语语法中占有特殊且重要的位置动词不定式、v-ing 及过去分词形式在句中均不能作谓语用，所以叫做非谓语动词 一、动词不定式：动词不定式由“to+ 动词原形 ”构成，如：to study, to play，动词不定式虽然不能作谓语动词用，但仍留着动词的特征，它可以带有所需要的宾语或状语而构成动词不定式短语，如：to study hard, to play table tennis 1、动词不定式的形式变化：动词不定式有下列时态和语态的形式变化 语态式 一般式 完成式 进行式 完成进行式主 动 to build to have built to be building to have beenbuilding被 动 to be built to have beenbuilt2、动词不定式的基本用法：动词不定式能起名词、形容词和副词的作用，可在句中作主语、表语、宾语补足语、定语和状语用，如： （1）作主语：To help each other is good.（动词不定式作主语时，一般可用 it 作形式主语，而将作主语的动词不定式置于句末，如：It is good to help each other. （2）作表语：My job is to drive them to the power station every day. 动词不定式在系动词 be 之后作表语，与表示将来时的 be + 动词不定式结构有所区别，如：Our plan is to set up another middle school for the peasants’ children.我们的计划是给农民子弟再成立一所中学。
（句中的谓语动词为 is，动词不定式to set up… 为表语，主语为 plan，但 plan 并不是动词不定式的逻辑主语，即动词不定式 to set up 所表示的动作不是主语 plan 产生的 ）We are to set up another middle school for the peasants’ children.我们将为农民的子弟再成立一所中学 （句中的 are to set up 整个结构为句中谓语，主语为 we，同时也是动词不定式 to set up 所表示的动作的逻辑主语，即动词不定式 to set up 所表示的动作是由 we 产生的） （3）作宾语：① 一些动词后只能用不定式作宾语，常见的这类词是表示命令、打算或希望2的，这类动词常用的有would like, want, decide, learn, need, agree, plan, wish, expect, hope, refuse口诀1：想要决定学习，需要同意计划，希望不要拒绝例：I hope to see her soon.She wants to go to university someday.② 常见的一些省略 to的动词不定式的句式：why not do…=why don’t you do..., had better (not) do…,would rather do…,could/would/will you please (not) do…例：I would rather stay at home. ③ it作形式宾语：在 find, think后跟不定式作宾语时，常用it代替，而将真正的宾语放在句末。
句式结构为：I find/think it + adj. + to do sth.例：We found it impossible to cross the river.作某些形容词的宾语：可以有动词不定式为宾语的形容词一般有○ 4glad, sorry, afraid, pleased, determined, willing, eager, anxious, ready, sure等，如：I am determined to give up smoking.（4）作宾语补足语① 在大多数双宾及物动词后，要用带to 的不定式，这类及物动词常用的有：allow, ask, help, invite, like, tell, want, warn, expect, wish, would like, encourage等结构为：ask/ tell sb. (not) to do sth. 例：They asked him to sing a pop song at the party.She wants her brother to go to university.② 在一些感官动词和使役动词后，要用不带to 的不定式。
help 有时也可用不带to 的不定式口诀：一感（feel）二听(hear, listen to)三让(make, let, have)四看(look at, see, watch, notice)半帮助(help)例: The boy saw two men enter the house.The young man made the old machine start working.The teachers helped the students (to) learn English well.本类动词在变成被动语态时，原句中作宾补的不定式前要加上to ，同时原来的宾补就变成了主语补足语例：Two men were seen to enter the house.（5）动词不定式在句中作宾语，如带有宾语补足语时，须先用 it 作形式宾语，而将该动词不定式后置，如：I don’t think it right to do it that way. （6）作定语：动词不定式作定语时，须位于被其修饰的名词或代词之后，如：Is this the best way to help him? 定语用的动词不定式如果是不及物动词，不定式后面就要用必要的介词，如：He is the man to depend on. 如果被不定式修饰的名词为 place, time, way，不定式后面的介词，习惯上可以省去，如：3eg1:I have no time to play (at). She has enough time to look after the children (with).eg2. The animals have to find a place to sleep (in) in winter.This is a good place for us to study (in).eg3. I don't like the way he speaks (in).I don't like the way he smiles (in).I don't like the way he cries (in).（7）作状语：动词不定式可以作下列状语：①目的状语：Every morning he gets up very early to read English.为了强调不定式表示目的的作用，可在不定式前加 in order to 或 so as to（以便或为了） ，但应注意 in order to 位于句首或句中均可，而 so as to 不能位于句首，如：She reads China Daily every day in order to （so as to） improve her English. 将表示目的的不定式置于句首，也可强调目的的作用，如：To master a foreign language, one must work hard at it. ②结果状语：They lived to see the liberation of their home town.他们活到亲眼见到了他们家乡的解放。
③enough + 形容词或副词 + 动词不定式，表示“ 足能……”的结果，如：You are old enough to take care of yourself now. too+形容词或副词 + 动词不定式，表示“太……而不能……”的结果○4如：I’m too tired to stay up longer.我太累了而不能再熬夜了注意：下列句子中的 too...to...结构不表示结果，也无否定含义：I’m only too glad to go. (= I’m very glad to go.)I shall be only too pleased to get home. (= I shall be very pleased to get home.) 〖 only too (adv.) 极; 非常; 太;很 〗在 “主语 +系动词 +表语（形容词）+ to do”结构中，句子的主语与动词不定式有○5逻辑上的被动关系，且形容词表示主语的特征或性质，这时，需用不定式的主动形式表示被动意思该结构中常用的形容词有：easy, hard, difficult, important, impossible, interesting, pleasant, nice, comfortable, safe, dangerous 等。
如：This question is easy to answer.这个问题容易回答This book is difficult to understand.这本书很难理解注：这种表示结果的不定式结构具有下列几个特点：① 不定式所表示的动作是随后发生的，如：He arrived late to find the others had gone home.He arrived late and found the others had gone home.② 不定式根据是否需要停顿而决定与主句是否用逗号隔开He left his native country (,) never to return.He returned home (,) to find his father lying sick in bed.③ 不定式所表示的结果往往含有“ 令人意想不到”的意味，其中以“使人不愉快的结果”较为常见 （有时也可以表示令人愉快、惊喜的结果） ，如：He went home to find his old friend George waiting for him.④ 不定式之前有时可以加上（but）only，以加强语气，此处也常为“使人不4愉快的结果” ，如：He got to the station only to be told the train had gone.They lifted a rock only to drop it on their own feet.注：不定式结构表示结果或表示目的，往往形式相似，这时，须根据词汇意义认真加以区别，试比较：He arrived late to find the others had gone home. ( = He arrived late and found the others had gone home.)He arrived late to avoid meeting Robe。