初二语法-不定式讲和练.doc

初二语法：动词不定式不定式就是“to+动词原型”，不定式在英文中可以充当很多成分。下面我们就一起来看一看不定式的几种用法。一、不定式做主语动词不定式作主语时，句子的谓语动词常用单数，不定式的位置有两种(1)不定式位于句首。如：To go to school by bike takes me half an hour every day. 我每天花半个小时骑车上学。(2)用it作形式主语，把真正的主语不定式放在句子的后面，常用于下列句式中.如：Itbe名词to doIts a good idea to go to the park on a nice day. 天气好去公园是个好主意。To go to the park on a nice day is a good idea. 就显得主语过长，句子头重脚轻，因而使用形式主语更利于清楚表达句子的结构。Itbe形容词for sb.to do It is so hard for a kid to answer a difficult question like this. 回答这样一个难题对于一个孩子来说太难了。Itbe形容词of sb.to doIt is nice of you to take care of my cat when Im busy.你真好能在我忙的时候照顾我的猫。difficult, easy, hard, important, impossible, necessary+for careless, clever, honest, kind, lazy, nice, right, silly, stupid, wise+of常见的区分for和of的例句还有这样一对： Its good for you to drink some water every day. Its very good of you to help me.It takes/took sb. +some time+ to do sth. It took him only 15 minutes to finish his homework.二、不定式做宾语(1)下面这些动词后面，只能跟不定式做宾语afford （付得起），agree（同意），arrange（安排），ask（要求），attempt （试图），choose（决定），decide（决定），determine（决心），expect（期待），fail（未履行），hesitate（犹豫），hope（希望），learn（学会），manage（设法），offer（主动提出），plan（计划），prepare（准备），pretend（假装），promise（答应），refuse（拒绝），want（想要）如：He asked his mom to buy him a new bicycle.他要求妈妈给他买一辆新自行车。At last, he chose to tell the truth.最终，他选择了说出事实。She decided to drop out of school because her family couldnt pay for her education.他决定辍学因为家里无力支付她的教育支出。He failed to finish his work on time.他没能按时完成工作。I hope to see you again soon.我希望能很快再次见到你。He managed to save his co-workers lives.他设法挽救了他同事的生命。My parents offered to take us to the teahouse.我父母提出带我们去茶馆。He planned to give his wife a surprise.他计划给他妻子一个惊喜。He promised to watch the show with us.他承诺和我们一起去看演出。(2)动词+ 疑问词+不定式动词后常常使用“疑问词+不定式”作动词的宾语。如：I dont know how to get to the airport from here.我不知道从这儿如何到机场。Please show us how to do that. 请演示给我们如何去做。He forgot when to start the meeting.他忘记了什么时候开始会议。三、不定式做定语1.不定式在做定语的时候，位置在被修饰的部分的后面。如：They dont have enough food to eat or enough places to live in.他们没有足够的食物吃，足够的地方住。My dream to become a teacher has come true at last.我当老师的梦想最终实现了。The next train to arrive is from Washington. 下一个到站的列车是从华盛顿来的。2.名词前有序数词或形容词最高级修饰的时候，名词后面的定语要用不定式。如：1.He is always the first student to arrive and the last to leave.2.It is the most suitable gift to buy.3.在“there be.”句型里，句子的主语是动词不定式动作的对象，常用主动式。如：1.Theres just so much to see and do here.2. but there are still many things to do there.不定式练习：1. Mrs. Smith warned her daughter _ after drinking.A. never to drive B. to never driveC. never drivingD. never drive2. The workers want us _ together with them.A. work B. working C. to work D. worked3. Therere so many kinds of tape-recorders on sale that I cant make up my mind _to buy.A. what B. which C. how D. where4. There isnt any difference between the two. I really dont know _.A. where to choose B. which to chooseC. to choose what D. to choose which5. “Have you decided when _?”-“Yes, tomorrow morning.”A. to leave B. to be leavingC. will you leave D. are you leaving6. Last summer I took a course on _.A. how to make dresses B. how dresses be madeC. how to be made dressesD. how dresses to be made7. He doesnt know _ to stay or not.A. whether B. if C. either D. if he will8. -The light in the office is still on. -Oh, I forgot _.A. turning it offB. turn it offC. to turn it off D. having turned it off9. We agreed _ here but so far she hasnt turned up yet.A. having met B. meeting C. to meet D. to have me10. She reached the top of the hill and stopped _ on a big rock by the side of the path.A. to have rested B. resting C. to rest D. rest11. I need a day or two _.A. to think it over B. to think over C. of thinkingD. to think over it12. Its freezing outside. You _ put on your overcoat.A. had better to B. had betterC. would better D. would better to13. The chair looks rather hard, but in fact it is very comfortable to _.A. sit B. sit on C. be sit D. be sat on14. Im hungry. Get me something _.A. eat B. to eat C. eating D. for eating15. -I usually go there by train.-Why not _ by boat for a change?A. to try going B. trying to goC. to try and go D. try going16. Ive worked with children before, so I know what_ in my new job.A. expected B. to expect C. to be expecting D. expects17. The problem _ at tomorrows meeting is a very difficult one.A. being discussed B. discussedC. to be discussed D. to discuss18. Tobby wanted to ride his bicycle in the street, but his mother told him_.A. not to B