1、Unit 4Global warming第四学时 Grammarit的用法()1it 在强调句中的用法it 可用来对句子谓语以外的某一成分进行强调，强调句的基本句型为：It动词be被强调部分who(m)/that其他部分。被强调部分指人，引导词用who/that均可，被强调部分是人，并且在句中作宾语时，可用whom/who/that引导。强调其他部分，一律用that。被强调的部分是原句的主语时，who/that之后的谓语动词在人称和数上与该主语一致。(1)It was Jane who paid for the meal yesterday.(It was Jane and not anoth
2、er person.)昨天的饭钱是简付的。(2)It was the meal that Jane paid for yesterday.(It was a meal and not something else.)简昨天付的是饭钱。2强调结构和主语从句句型(Itbeadj./n.that其他部分)的区别(1)强调结构可以翻译成“正是”或“就是”。(2)含有主语从句的句子删掉It be.that/who，则原句在结构上和意义上均不成立，而强调结构若去掉结构标志后，原句在结构上和意义上仍然成立。It is I that/who am your true friend.我才是你真正的朋友。(这是强
3、调句，去掉It is.that/who后，句子仍然成立。)It is necessary that you should master at least one foreign language.你有必要掌握至少一门外语。(It作形式主语，代替后面由that引导的主语从句，去掉It is.that后，句子不能成立。)3强调句型和It动词一段时间before/when/that/since句型的区别(1)强调句型：Itis/was被强调部分who(m)/that其他部分。It was not until he came back that his mother went to bed.(2)It
4、 is时间段since 从句(一般过去时/过去完成时)。Its years since we enjoyed ourselves so much.我们已有好多年没有这么开心过了。(3)It was/will be时间段before 从句(一般过去时/一般现在时)。It was not long before he joined the Party.不久，他就入了党。(4)It was时间点when从句(一般过去时)。It was 12 oclock when he came back to school.(这不是强调句。it指时间，when引导时间状语从句。)比较：It was at 12 o
5、clock that he came back to school.(这是强调句，强调时间状语at 12 oclock，去掉It was.that，句子仍然成立。)4对于特殊疑问句强调的句式是“疑问词is/wasitthat其他部分”What is it that Rosa has found in the living room?露莎在起居室里发现的是什么？I dont know what it is that Jimmy has done in his study.我不知道吉米在书房里干什么。Do you still remember where it was that you first came across Paul three years ago?你还记得三年前是在哪儿第一次见到保罗的吗？
