初三英语上册知识点（全)语法复习动词不定式一. 定义：由to+动词原形构成。不定式是一种非限定性动词。而非限定动词是指那些在句中不能单独充当谓语的动词，可分为不定式，动名词，现在分词和过去分词。“动词不定式”由动词+不定式构成。动词不定式在句中可以作句子除谓语之外的任何句子成分。动词不定式的被动形式除了一般形式外还有其完成式和进行式。二. 动词不定式的构成：to+动词原形 作主语动词不定式作主语时，句子的谓语动词常用单数，其位置有以下两种：(1)把不定式置于句首。如：To get there by bike will take us half an hour.(2)用it作形式主语，把真正的主语不定式置于句后，常用于下列句式中。如：It+be+名词+to doIts our duty to take good care of the old.It takes sb+some time+to doHow long did it take you to finish the work?It+be+形容词+for sb+to doIt is difficult for us to finish writing the composition in a quarter of an hour.It+be+形容词+of sb+to doIt is stupid of you to write down everything (that) the teacher says.It seems(appears)+形容词+to doIt seemed impossible to save money.在句型中，常用表示客观情况的形容词，如：difficult,easy,hard,important,impossible,necessary 等；在句型中，常用careless,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise等 表示赞扬或批评的词。在不定式前的sb，可看作其逻辑主语。这一句式有时相当于Sb is+形容词+to do句式 ，如：Its kind of you to help me with my English.=You are kind to helpme with my English.(3)举例（1） Its easy (for me) to do that.我做这事太容易了easy,difficult,hard,important,possible,impossible,comfortable,necessary,better;the first,the next,the last,the best,too much,too little,not enoughIts so nice to hear your voice.听到你的声音真高兴。Its necessary for you to lock the car when you do not use it.当你不用车的时候，锁车是有必要的。（2） Its very kind of him to help us.他帮助我们，他真好。Kind,nice,stupid,rude,clever,foolish,thoughtful,thoughtless,brave,considerate(考虑周到的),silly,selfish(自私的)例句:It was silly of us to believe him.我们真愚蠢，竟然相信了他。It seemed selfish of him not to give them anything.他不给他们任何东西，这显得太自私了。注意：（1） 其他系动词如，look，appear等也可用于此句型（2） 不定式作为句子成分时，动词用单数形式。（3） 当不定式作主语的句子中又有一个不定式作表语时，不能用It is to的句型(对)To see is to believe.眼见为实。(错)It is to believe to see.三. 动词不定式作宾语 后面能接不定式作宾语的动词有：agree, ask, choose, decide, forget, hope, learn, want, wish, would like等。 We hope to get there before dark. 我们希望天黑以前到那儿。 The man decided to do it herself. 那个男人决定自己做那件事。动词不定式作宾语的注意事项（2点）1. 有些动词既可跟不定式作宾语，也可跟动名词作宾语，但含义不同： remember to do 记住要做某事 remember doing 记得曾经做过某事 forget to do忘记要做某事 forget doing 忘记曾经做过某事 stop to do 停下来去做某事 stop doing 停止做某事 go on to do 继续做另一件事 go on doing 继续做原来在做的事 2. 不定式作宾语时，如带有宾语补足语，则要把不定式放到后面，用it作形式宾语，构成“主语+动词+it+宾补（形容词、名词）+不定式”结构。如：He found it very difficult to get to sleep. 他发现很难入睡。四. 动词不定式作宾语补足语 1. 后面能接to不定式作宾语补足语的动词有：ask, order, teach, tell, want, wish, help等。 The teacher told us to do Exercise 1. 老师要我们做练习一。 I want both of you to go. 我要你们俩去。We helped her (to) repair her bike. 我们帮助她修理自行车。2. 使役动词let, have, make及感官动词see, watch, notice, hear, feel等要以不带to的不定式作宾补。 Lets have a rest. 我们休息一会吧。 I saw him come in. 我看见他进来了。 感官动词后既可跟不带to的不定式作宾补，也可跟v-ing作宾补，前者表示动作的全部过程已结束；后者表示动作正在进行。 I saw him come downstairs.我看见他下了楼。（说明他下楼了这件事） I saw him coming downstairs.我看见他在下楼。（说明他下楼时的情景）五. 动词不定式作状语Later he left home to work in different cities. 不久他离开家到不同的城市工作。He went to see a football match. 他去看足球比赛了。In order to catch the other students, I must work hard. 为了赶上其他同学，我必须努力学习。六. 动词不定式作定语不定式作定语一般放在所修饰的词的后面。I need something to eat. Do you have something to read?Tom was so excited that he had no word to say.He is really a fool only to eat.The man to stand here just now is our English teacher.The doctor had no way to save the patient.注意：（1）作定语的不定式是由及物动词组成，被修饰的名词或代词与不定式之间存在方位或方式关系需要有介词。I am looking for a room to live in. 我正在找一间住房。（方位关系）We have many things to do experiments with. 我们有许多做实验的东西（方式关系）（2）作定语的不定式是由“be + adj + prep”构成的动词短语。Here there isnt any book for me to be interested in.We have done many things to proud of. 我们做了许多引以自豪的事。七. 动词不定式作主语To give is better than to receive. To reach there on foot is impossible.动词不定式作主语时，可以用it 代替，把实际主语不定式放在后面。Its better to give than to receive.Its impossible to reach there on foot.Its + adj + for sb. to do sth.Its not difficult for me to study English well.Its easy for him to work out this math problem.在这个句型中，如果形容词与不定式的逻辑主语关系密切，并且形容词用来说明逻辑主语的性质、品质、特点等，由of引出逻辑主语。这类形容词主要有nice, kind, good, wrong, right等。 八. 动词不定式和疑问词连用动词不定式可以和疑问词what, which, how, where, when连用，构成不定式短语，可以作主语、宾语、表语、宾语补足语等。How to do is still a question. Have you decided when to leave? 九. 动词不定式的否定形式 动词不定式的否定式是在to前加not；不带to的不定式则在动词前加not. 如： Zhang Ming asked me not to stay at home all day. 张明要我不要整天呆在家里。 My mother let me not do it by myself. 妈妈让我不要独自做这件事。被动语态英语有两种语态：主动语态和被动语态主动语态（The Active Voice）表示主语是动作的执行者。被动语态（The Passive Voice）表示主语是动作的承受者。构成：承受者+助动词be+及物动词的过去分词+by+执行者一般现在时：承受者+助动词am / is/are +及物动词的过去分词+by+执行者一般过去时：承受者+助动词was / were +及物动词的过去分词+by+执行者承受者+助动词shall / will be+及物动词的过去分词+by+执行者承受者+助动词 have/ has be