外研版选择性必修二Unit4-Grammar—It-as-an-empty-subject课件.pptx

1、Breaking boundariesUnit 4Period FourGrammarIt as an empty subject达标检测 当堂检测 基础达标演练语法导学 感悟规律 重点难点剖析内容索引内容索引感知以下课文原句感知以下课文原句，完成完成方框方框下的小题下的小题1.But it is vital not to take any chances.2.It is important to remember that Ebola doesnt respect national boundaries.3.It is so inspiring to have colleagues like

2、 Wilton.4.It is no use crying over spilt milk.5.It is no good sighing about your failure；youd better start again.6.It makes me angry that he doesnt study hard.7.It is not clear whether they consider this opinion or not.语法感知语 法 导 学感悟规律 重点难点剖析1.以上句子中，句以上句子中，句1、2、3中中it作形式主语，真正的主语是后面作形式主语，真正的主语是后面的的 。2.

3、句句4、5中的中的it代替的真正的主语代替的真正的主语是是 。3.句句6、7中的中的it代替的真正主语是代替的真正主语是由由 引导引导的从句。的从句。动词不定式动词不定式动名词动名词that或或whether一、一、it代替不定式作形式主语代替不定式作形式主语不定式不定式(短语短语)作主语时往往主语太长，句子结构不平衡，此时可用作主语时往往主语太长，句子结构不平衡，此时可用it作作形式主语，把不定式短语放在句末。常用于下列句型中：形式主语，把不定式短语放在句末。常用于下列句型中：1.Itis/wasadj./n.to do sth.(不定式前可有其逻辑主语不定式前可有其逻辑主语for/of s

4、b.)In fact it is a hard job for the police to keep order in an important football match.事实上，警察在一场重要的足球比赛中维持秩序是一项艰巨的工作事实上，警察在一场重要的足球比赛中维持秩序是一项艰巨的工作。It is very kind of you to give me a hand in time.你能及时帮助我真是太好了你能及时帮助我真是太好了。语法精析It is difficult for so little a boy to finish the task in such a short time

5、.对于一个这么小的男孩来说，在如此短的时间内完成这项工作太难了。对于一个这么小的男孩来说，在如此短的时间内完成这项工作太难了。2.Itv.to do sth.动词不定式作主语时除动词动词不定式作主语时除动词be以外，动词以外，动词take，cost，need，require，make，sound，occur 等也可用等也可用it作形式主语，而把动词不定式放在后面。作形式主语，而把动词不定式放在后面。It took us three years to complete the project.我们花费三年时间才完成了这项工程我们花费三年时间才完成了这项工程。It sounds reasonabl

6、e to do it this way.听起来这样做有道理。听起来这样做有道理。It needed hard work to finish the job.要完成这项工作需要努力工作要完成这项工作需要努力工作。It didnt occur to me to ask him to help me.我根本没想到要找他帮忙。我根本没想到要找他帮忙。温馨提示温馨提示动词不定式作主语，一般情况下用动词不定式作主语，一般情况下用it作形式主语，而把动词不定式放在后面。作形式主语，而把动词不定式放在后面。也可以直接用不定式作主语。也可以直接用不定式作主语。It is wrong to tell lies.T

7、o tell lies is wrong.撒谎是不对的。撒谎是不对的。但在疑问句和感叹句中，只能用但在疑问句和感叹句中，只能用it作形式主语。作形式主语。Isnt it a good idea to have a walk around?出去兜一圈难道不是一个好主意吗？出去兜一圈难道不是一个好主意吗？What a pleasure it is to work with you!同你一起工作是多么愉快啊！同你一起工作是多么愉快啊！二、二、it代替动名词短语作主语代替动名词短语作主语It is no use reasoning with him.跟他讲道理是没有用的。跟他讲道理是没有用的。It i

8、s no good reading in dim light.在昏暗的光线下看书不好在昏暗的光线下看书不好。温馨提示温馨提示it作形式主语代替动名词短语时，往往限于以下句型中：作形式主语代替动名词短语时，往往限于以下句型中：It is no good/no use/fun/a waste of time.等中，如不是上述句型，在将动名词移到句尾用等中，如不是上述句型，在将动名词移到句尾用it作形式主语时，动名词要改为不定式。作形式主语时，动名词要改为不定式。Collecting stamps is one of his hobbies.It is one of his hobbies to c

9、ollect stamps.集邮是他的爱好之一。集邮是他的爱好之一。三、三、it代替从句作主语代替从句作主语用用it 作形式主语的结构主要用于下列句型：作形式主语的结构主要用于下列句型：1.It be名词从句：这样的名词有名词从句：这样的名词有a fact，a surprise，an honor，a pity，common knowledge 等。等。It is common knowledge that the full moon brings fair weather.皓月皓月兆天晴，这是常识。兆天晴，这是常识。It is a surprise that you gave such an

10、answer to the question.你你对这个问题作了这样的回答，令人吃惊。对这个问题作了这样的回答，令人吃惊。2.It be形容词从句：这样的形容词有形容词从句：这样的形容词有natural，true，strange，necessary，important，obvious，certain，wonderful，funny，possible，likely，probable等。等。It is certain that free medical care will be given to most people in our city.我们城市的大多数人将享受免费医疗，这是肯定的。我们城市

11、的大多数人将享受免费医疗，这是肯定的。It is probable that he has known everything.很可能他已经知道了一切。很可能他已经知道了一切。3.It动词从句：这样的动词有动词从句：这样的动词有seem，happen，appear，look，matter，make，strike，occur(突然想起突然想起)等。等。It appeared that he had a taste for music.看来他对音乐有一定的鉴赏力。看来他对音乐有一定的鉴赏力。It made us very happy that she was saved.她能化险为夷令我们大家非常高

12、兴。她能化险为夷令我们大家非常高兴。4.Itbe分词从句：这样的分词有分词从句：这样的分词有 said，reported，believed，known，decided，proved，thought，expected，announced，arranged，amusing，puzzling，striking等。等。It is said that Li Hao has been to Europe.据说李昊去过欧洲。据说李昊去过欧洲。It was amusing that a rabbit ran out of the empty box on the desk.桌上的空盒子里竟然跑出来一只兔子，太

13、有趣了。桌上的空盒子里竟然跑出来一只兔子，太有趣了。温馨提示温馨提示大部分连接词引导的主语从句都可以用大部分连接词引导的主语从句都可以用 it充当形式主语。充当形式主语。It remains unknown when they are going to get married.他们他们何时结婚还不知道。何时结婚还不知道。It says in the newspaper that the enemy has been defeated.报纸报纸上说敌人已经被打败了。上说敌人已经被打败了。It depends on the weather whether we will go.我们去不去取决于天气

14、。我们去不去取决于天气。返 回.单句语法填空单句语法填空1.happened that the tickets were sold out.2.Its a waste of time (reason)with him.3.It was foolish you to leave school at such a young age.4.It was pretty hard him to bring up the child on his own.5.It suddenly occurred to him he had left his keys in the office.达 标 检 测当堂检测

15、 基础达标演练reasoningItofforthat6.It is extremely obvious she has been lying about her identity.7.It is necessary (use)a short-wave radio to pick up the programmes.8.Its standard practice for a company like this one (employ)a security officer.9.It remains to be seen the newly formed committees policy can

16、 be put into practice.10.It (require)that you should not tell other people the password of your e-mail account.thatto useto employwhetheris required.完成句子完成句子11.It is my pleasure .我很高兴在会上发言。我很高兴在会上发言。12.It was brave in public.她能在公共场合讲话，真勇敢。她能在公共场合讲话，真勇敢。13.to make gifts to children.给孩子们做礼物没有坏处。给孩子们做礼

17、物没有坏处。14.It is fun in the early morning.在清晨游泳很愉快。在清晨游泳很愉快。to speak at the meetingof her to speak outIt does no harmgoing for a swim15.for leaves to fall from the trees in the fall.秋天树叶从树上落下是常见的。秋天树叶从树上落下是常见的。16.some people were killed in the downtown.据报道，一些人在市中心被杀。据报道，一些人在市中心被杀。17.they will be fired by the company because of their fault.他们很可能因为自己的过错而被公司解雇。他们很可能因为自己的过错而被公司解雇。18.Jim will be fit enough to play in the finals.吉姆是否适合参加决赛还有待观察。吉姆是否适合参加决赛还有待观察。返 回Its commonIt is reported thatIt is likely thatIt remains to be seen whether本课结束