Unit 4 Breaking boundaries Using language课件2022-2023学年高中英语外研版选择性必修第二册

UNIT 4 Breaking boundaries Using language 1 it 作形式主语 [观察例句]1.It is difficult for a foreigner to learn Chinese.2.It's kind of you to help me.3.It is no use talking to him about it.4.It is a mystery to me how it all happened.5.It is believed that the flood there is the biggest in 100 years. [归纳用法]it作形式主语时没有具体的意义,只是帮助把真正的主语移到句子后面去,使句子显得平衡。it作形式主语时,真正的主语通常是不定式短语、 ing短语或主语从句。 一、不定式短语作真正的主语,常用于下列句型中: It + be +形容词 + (for/of sb.) to do sth. It + be + 名词 + to do sth. It takes sb.some time to do sth.干……花了某人……时间 It's up to sb.to do sth.干……是某人的职责或义务 It is everyone's duty to obey the law. 遵守法律是每个人的义务。 It took them a year to build the bridge. 建这座桥花了他们一年的时间。 It is bad manners to stare at people. 盯着人看是不礼貌的。 It is up to us to help those in need. 帮助那些有困难的人是我们的责任。 [名师点津] 在“It+be+形容词+for/of sb.to do sth.”句型中,如果形容词描述的是sb.,则应用介词of;如果描述的是to do sth.就用for。 It's necessary for us to use a short wave radio to pick up the programmes. 我们用一台短波收音机收听这些节目是必要的。 It was foolish of him to give up the job. 他放弃那工作是愚蠢的。 [即学即练1] 用所给词的适当形式填空 ①It is not up to you _(tell) me how to do my job. ②It is not right _(use) these places as rubbish dumps. ③It was nice of them _(invite) us. to tell to use to invite 二、 ing短语作真正主语的情况远不及不定式短语那么普遍,常限于no good, no use, useless, waste等词的后面。 It is no good/ use having a car if you can't drive.有车如果不会开是没有用处的。It is a waste of time watching TV.看电视是浪费时间的。 It is no use asking him.问他没有用。 [即学即练2] 用所给词的适当形式填空 ①It's no good _(take) over the experience of foreign countries uncritically. ②It's no use _(cry) over spilt milk. ③It is worth _(make) an appointment before you go. taking crying making 三、用it作形式主语,主语从句作真正主语的常见句型有: 1.It is a pity/ a shame/ a fact/ an honour/ good news/ no wonder/ a wonder... that... It was a pity that the engineer couldn't come. 可惜工程师没能来。 2.It is + 形容词(如: strange/ natural/ surprising/ obvious/ true/ fortunate/ wonderful/ funny/ possible/ impossible/ likely/ unlikely/ clear/ unusual/ certain/ important...)+that... It is certain that he will win. 他一定会取胜。 3.It seems/ h