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课件网) 人教新目标Go For It九年级英语全册 Unit12 Life is full of the unexpected SectionA Grammar Focus-4c New words n.街区 n.工作者；工人 v.盯着看；凝视 n.不信；怀疑 prep.在……上面 adv.在上面 v.着火；燃烧 (burnt, burnt; burned, burned) block worker stare disbelief above burn Presentation Grammar Focus 探究语法规律 探究一：过去完成时的结构和用法 过去完成时还可表示过去某一时刻之前发生的动作或状态持续到过去某个时间或持续下去，常与for, since等词连用。 例: When Jack arrived, Mary had been away for almost an hour. 当杰克到时，玛丽已经离开快一个小时了。 My grandmother had been dead since November last year. 用所给词的适当形式填空。 1. When I got there the bus _____ (go). 2. By the time I got to class, the teacher _____ (start) teaching. 3. We _____ (learn) over 1,000 words by the end of last term. 4. I _____ (clean) the room before he arrived here. 【实战演练】 had gone had started had learnt had cleaned Learn to walk before you run Grammar Focus When I got to school, I realized that I had left my backpack at home. By the time I got back to school, the bell had rung. Before I got to the bus stop, the bus had already left. I was about to go up to my office when I decided to get a coffee first. As I was waiting in line with the other office workers, I heard a loud sound. Read the sentences below, and circle the conjunctions of clauses and underline the tense. Learn to walk before you run By the time I got back to school, the bell had rung. 一般过去式 从句 主句 过去完成时 动作发生在后 动作发生在前 在过去某个时间或某个动作之前发生的动作或存在的状态，它表示动作发生的时间是“过去的过去”。 定义 Learn to walk before you run Presentation Grammar Focus 探究语法规律 探究一：过去完成时的结构和用法 by the time 的用法 by the time 意为“到……时候(为止)”, 是一个介词短语, 在句中常起到连 词的作用, 引导时间状语从句。 1.如果从句中的谓语动词是一般过去时, 那么主句的谓语动词通常用过去 完成时, 表示“截止到从句动作发生时, 主句动作已经完成, 即过去的过去”。 例：By the time you came back, I had finished this book. 你回来时我已经把这本书看完了。 （从句谓语动词came back 为一般过去时, 所以主句动作用过去完成时had finished, 表示过去的过去。） 2. 如果从句中的谓语动词为一般现在时或现在完成时, 那么主句中的谓语动词常用将来完成时, 表示“截止到将来的某一时刻为止, 主句动作将已完成”。 例：By the time I get home, they will have left. 我到家时他们将已经离开。 By the time I graduate next year, I will have lived here for five years. 到明年毕业时, 我将已经在这待了五年了。 Learn to walk before you run 1)在过去某一时刻或动作之前已经发生或完成了的动作 标志词： by、by the end of +过去的时间点/动作 before、by the time 、until +时间状语从句(一般过去时) 具体用法 Learn to walk before you run 主句为过去完成时，从句是一般过去时，主句动作发生在从句之前。 两个动作同时进行，主从句都是一般过去时或过去进行时。 When I got to school, I realized that I had left my backpack at home. By the time I got back to school, the bell had rung. Before I got to the ... ...
