Unit 4 Global warming “it”的用法（二）【观察】观察下列几组句子中it的用法，然后加以总结。1. a. It was for this very reason that Mr. Li came to work late this morning.b. It was a professor from Peking University who / that gave us a speech yesterday. 2. a. It must be the naughty boys who are making so much noise. b. It might have been at midnight that the traffic accident took place. 3. a. Is it in this factory that your father worked 20 years ago? b. Was it on the bus that you had your cellphone stolen yesterday? 4. a. What is it that your boyfriend has bought you as a birthday present? b. When and where was it that you met Jim for the first time? 5. a. It is simply because I like it that I do it.b. It is what you do rather than what you say that matters.6. a. I wonder what it is that has caused him to change his mind. b. He asked me why it was that I hadnt turned up at the party. 【总结】通过观察以上例句，可将it的用法归纳如下： 强调句型的基本句式是“It is / was +被强调部分+ that / who +句子的其余部分”，它可以对句中除谓语动词以外的成分加以强调。被强调部分指人时，用who或that；指事物时用that。（如第1组例句） 在强调结构中，be前可使用表示推测的情态动词。（如第2组例句） 强调句型的一般疑问句形式是：Is / Was it +被强调部分+ that / who +句子的其余部分。（如第3组例句） 强调句型的特殊疑问句形式是：疑问词+ is / was it that +句子的其余部分。（如第4组例句） 强调句型也可强调状语从句、名词性从句等。（如第5组例句） 强调句型的特殊疑问句形式还常出现在宾语从句中。（如第6组例句）【拓展】 强调主语时，谓语动词应与之保持一致。如：It is I who am to go there together with you. 如果被强调的是not . until引导的时间状语（从句），用It is / was not until . that .结构。注意：此时not until不能分开。如：It was not until I had finished all my homework that I went to bed last night. 注意不要混淆强调句和定语从句：It is / was . that . 为强调句标志，去掉后仍可组成一个完整的句子；定语从句不具备这一特征。比较：It was at ten oclock that my husband got home last night.（强调句） = My husband got home last night at ten oclock.It was ten oclock when my husband got home last night.（when引导定语从句）【高考链接】从、B、C、D 四个选项中，选出可以填入空白处的最佳选项。1. It was not until near the end of the letter _ she mentioned her own plan. (天津2013)A. that B. where C. why D. when2. It was only after he had read the papers _ Mr. Gross realized the task before him was extremely difficult to complete. (2013 新课标全国卷II)A. when B. that C. which D. what3. It was with the help of the local guide _ the mountain climber was rescued. (重庆2013)A. who B. that C. when D. how4. Was it by cutting down staff _ she saved the firm?No, it was by improving work efficiency. (上海2012)A. when B. what C. how D. that5. It was 80 years before Christopher Columbus crossed the Atlantic _ Zheng He had sailed to East Africa. (重庆2012)A. when B. that C. after D. since答案【高考链接】1-5 ABBDB4