Unit 4 Global Warming Period3 GrammarLearning aims: 1. Review the use of “it” 2. Learn useful “it” structuresImportant point: Learn emphatic sentence.Difficult point: Master the use of” it”.使用说明及学法指导:1. 通过自学同步检测 P,完成预习案。2. 完成时间:30 分钟。预习案 Previewing CaseTask 1 写出“it”在句中指的内容。1) Guangzhou is a beautiful city, isn’t it? ( )2)You’ve helped me a lot; I’ll never forget it. ( )3)— What’s this? — It’s a computer. ( )4)— Whose book is that? — It's hers. ( )5)It’s time for lunch.( )6)It’s raining hard.( )7)It’s two miles from the school to our home.( )8)It is easy to buy a new radio. ( )9)It is no use telling him that. ( )10) It is exciting that we can do what we like to do. ( )11) I feel it my duty to help him. ( )小结: it 可以代替______ ,______和上文的_____;it 可以指时间,_______, ______,环境,度量等;it 作形式_____或_____代替动词不定式,动名词和从句。Task 2 it 替代 to do 作形式主语或宾语1) It takes sb. ... to do sth. 做...要花费某人修建长城花了成千上万的人力和大量的时间。___________________________________________________________________to build the Great Wall.2)It is adj+ (kind,bad , brave ,careless, clever, cruel, foolish ,stupid ,wise ,wrong等形容逻辑主语特征) of sb to do sth.你重复相同的错误真的很笨。______________________________________________________________3)It is adj /n + for sb. to do sth. 常用形容词:important, necessary, natural, easy, safe, common, normal ,hard, difficult ,dangerous 等;名词:idea, habit, pity, shame, time, surprise, wonder 等彼此帮助对我们来说非常重要。___________________________________________________________去野炊是一个好想法。____________________________________________________________________4) think\believe\make\find\consider\feel 等+it + adj\n (for/of...