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1、授课：希希Activity 1读句感悟阅读下列句子，认真感悟加颜色部分，并完成方框下的小题。(1)However，during this period，it can be easy for some of them to form bad habits.(2)To prevent harmful habits like these from dominating a teenagers life is essential.(3)To change bad habits is never easy，even with many attempts.(4)After all，it is not ea
2、sy to break bad habits.1.以上句子中动词不定式都是作 。2.句(1)和句(4)中it作 ，真正的主语是后面的 。主语形式主语动词不定式Activity 2语法精析一、基本用法动词不定式作主语时，谓语动词用单数。To look after these naughty boys is really difficult.照看这些淘气的男孩真的很难。为了避免头重脚轻，常用it作形式主语放在句首，作主语的不定式常置于句末。It would be better for you to go there.你还是去那里的好。Observe and Discover1.It isnt ri
3、ght to talk like that.2.Its difficult to master English.3.Its hard for me to answer the question.4.It is better to have loved and lost than never to have loved at all.以上四个句子有两点共同之处：以上四个句子有两点共同之处：1.句子的真正主语都是句子的真正主语都是_，但都使用，但都使用it作形式主语；作形式主语；2.句子的表语都是句子的表语都是_。动词不定式动词不定式形容词形容词it+be+adj+(逻辑主语逻辑主语)+to do
4、 sth Observation 4Discover 4Observe and Discover动词不定式的逻辑主语常用动词不定式的逻辑主语常用_ _ 来表示，当形容词修饰动来表示，当形容词修饰动词不定式时，此时常用介词词不定式时，此时常用介词_。当表语形容词表示不定式的逻。当表语形容词表示不定式的逻辑主语的性质或特征时，则用介词辑主语的性质或特征时，则用介词_。1.It isnt right for us to stop half way.=To stop half way is not right.2.Its kind of you to think so much of us.=You
5、are kind to think so much of us.for/of+sb forofObservation 5Discover 5Its very easy for him to work out this math problem.对他来说解出这道数学题很容易。It was careless of him to make such a mistake.He was careless to make such a mistake.犯了这样的错误，他太粗心了。二、动词不定式和动名词作主语的异同点1.动名词和不定式作主语的相同点(1)不定式和动名词作主语时，常常为了保持句子的平衡，用it
6、来作形式主语，如：It is not easy to learn English well.学好英语不容易。It is no use asking him for help.向他求助是没有用的。(2)如果主语用了不定式，表语和宾语也要用不定式；主语用了动名词，表语和宾语也要用动名词，这在英语中称为对称性，如：To see is to believe.Seeing is believing.眼见为实。It is better to stay home than to go out.待在家里比出去要好。Observe and Discover1.To see is to believe.2.To
7、do this is to cut the foot to fit the shoe.3.To say is one thing and to do is another.4.To make a detailed plan is a good idea to make it successful.Observation 12.动名词和不定式作主语的不同点(1)不定式作主语常表示具体的某一动作；表示泛指或一般的抽象的概念时，多用动名词。Walking is a good form of exercise for both the young and the old.散步是一种老少皆宜的很好的运动
8、形式。Further thinking1._(do)morning exercises regularly is good for your health.2.It feels really good _(do)morning exercises today.Doingto do Complete the following sentences and compare their usages.(2)在“Itbeno use(good/help/need等)”之后常用动名词作主语，而少用不定式。It is no use crying over the split milk.覆水难收。It is
9、 no help taking this medicine.服用这种药没有用。注意：如果该句型中用了for引出不定式的逻辑主语，就只能用不定式。It is no good for us to do that exercise.我们做那种练习没有好处。(3)不定式可以和when，where，how，what，whether等连用，在句子中作主语、宾语和表语，而动名词则不能。Where to put the box seems hard to decide.很难决定把这个箱子放在哪里。Whether to do it hasnt been decided.是否做这件事还没定下来。返 回Observ
10、e and Discover1.How to use the computer is a question.2.Where to put the bikes is being discussed.3.When and where to have the meeting has not been decided._和动词不定式构成不定式短语作主语。疑问词包括疑问代词和动词不定式构成不定式短语作主语。疑问词包括疑问代词who、whom、what、which、whose以及疑问副词以及疑问副词when、where和和how。此外连接词此外连接词whether也适用。也适用。此时，疑问词此时，疑问词
11、+to do 结构可以转化为一结构可以转化为一个个_，例如：，例如：How to use the computer is a question.=_疑问词疑问词主语从句主语从句How we can use the computer is a question.Observation 8Discover 8Observe and Discover1.It took me more than an hour to do my homework yesterday evening.2.It will take us a long time to walk there.3.How long does
12、it take to get there?4.How much did it cost you to send the package?Observation 7Discover 7以上四个句子是动词不定式作真正主语，由以上四个句子是动词不定式作真正主语，由 it 作形式主语引导的作形式主语引导的句子，它们的谓语是句子，它们的谓语是 _。它们的共同句式是它们的共同句式是_，表示某人花多少时间或金钱做某事。，表示某人花多少时间或金钱做某事。take/costit takes(costs)sb some time/money todosth.翻译句子1.被邀请参加玛丽的生日派对是很荣幸的事情。_2
13、.我们难以在15分钟内写完这篇作文。_3.你把老师说的所有东西都记下来是愚蠢的。_Its a great honour to be invited to Marys birthday party.It is difficult for us to finish writing the composition in a quarter of an hour.It is stupid of you to write down everything the teacher says.4.爱与被爱是一个人所能寻找的最大的幸福。_5.他不给他们任何东西，这显得太自私了。_To love and to b
14、e loved is the greatest happiness one can seek.It seemed selfish of him not to give them anything.1.(英语说得流利)is my dream.I am completely aware that it is difficult 2.(流利地说英语).So I asked my English teacher for help straight away.She gave me some advice.First of all，it is necessary for you 3._ (在任何可能的时候说英语).Besides，it is very important 4.(练习正确的发音).All in all，it is possible for you 5.(擅长英语口语)if you are hard-working enough.运用所学不定式作主语的知识补全下面短文To be fluent in Englishto speak English fluentlyto speakEnglish whenever possibleto practice correct pronunciationto be good at oral English返 回