Unit 12 Life is full of the unexpected 重点单词：unexpected, kick, block, oversleep, burn, announce, embarrassed, cancel, believable 等。 重点短语：be full of, give a lift, end up, in line with, show up, sell out, by the time等。 重点句型：before，by the end of last year，by the time 引导的时间状语从句。 语法要点：过去完成时had done的构成和用法；时间状语从句与主句的时态搭配。 【过去完成时】 过去完成时：表示过去某一时间或动作以前已经发生或完成了的动作。它表示动作发生的时间是“过去的过去”。表示过去某一时间可用by, before等构成的短语，也可用when, before等引导的从句或通过上下文提示等。 过去完成时的构成： 1）过去完成时基本构成形式: had +过去分词。 The train had left when I arrived at the station this morning. 2）过去完成时的否定形式: had + not + 过去分词。 John hadn’t went to bed when his parents got home at the midnight of yesterday. 3）过去完成时的一般疑问句及其回答形式: 疑问句要把had提到句首；回答用Yes, 主语+ had. / No, 主语+ hadn’t. —Had he told you the place before the meeting was held yesterday —Yes, he had. (No, he hadn’t.) 过去完成时的用法： a.在told, said, knew, heard, thought等动词后的宾语从句。 She said (that) she had never been to Paris. b. 状语从句 在过去不同时间发生的两个动作中，发生在先，用过去完成时；发生在后，用一般过去时。 When the police arrived, the thieves had run away. c. 表示意向的动词，如hope, wish, expect, think, intend, mean, suppose等，用过去完成时表示"原本…，未能…" We had hoped that you would come, but you didn't. 3)过去完成时的时间状语before, by, until , when, after, once, as soon as。 He said that he had learned some English before. By the time he was twelve, Edison had began to make a living by himself. Tom was disappointed that most of the guests had left when he arrived at the party. 典型例题 The students ___ busily when Miss Brown went to get a book she ___ in the office. had written, left B，were writing, has left C. had written, had left D. were writing, had left 解析："把书忘在办公室"发生在"去取书"这一过去的动作之前，因此"忘了书"这一动作发生在过去的过去，用过去完成时。句中when表示的是时间的一点，表示在"同学们正忙于……"这一背景下，when所引导的动作发生。因此前一句应用过去进行时。答案D At the end of the meeting, it was announced that an agreement (reach). 解析：会议结果宣布之前，已经达成了一致。答案had been reached 【巩固练习】 I. 语法选择。 1. When I arrived at the station, the train _____ already. A. left B. has left C. had left D. leaves 2. By the time he came back, we _____ the work for hours. A. had done B. have done C. did D. are doing 3. She _____ her homework before her mother came back last night. A. has finished B. finished C. had finished D. will finish 4. They _____ the bridge by the end of last year. A. have built B. built C. had built D. were building 5. He _____ the book for three weeks before he returned it to the library. A. has kept B. kept C. had kept D. keeps 6. By the time she got to the airport, her flight _____. A. had left B. left C. was leaving D. had been left 7. We _____ ou ... ...
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