2017-2018届高考英语一轮复习 第二部分 基础语法突破 专题十一状语从句学业水平测试课件.pptVIP

* 第二部分 基础语法突破 从句动作与主句动作可以是同时发生，也可以是先后发生。 When he finished writing the report, he went to chat with his parents. 写完那份报告后，他就去跟父母聊天了。 When my mother cleaned the room, I was washing clothes. 我妈妈打扫房间时我正在洗衣服。 when 用法 引导词 从句动作与主句动作同时发生。意为“一边……一边……；随着”。 The students took notes as they listened. 学生们边听课边做笔记。 As you grow older, youll know better and better about yourself. 随着年龄的增长，你会越来越了解自己。 as 当两个延续性动作同时发生且具有对比意味时，常用while。 While she was making a call, I was writing a letter. 她打电话时，我正在写信。 从句的谓语动词必须是延续性的，强调主句动作与从句动作同时发生。 While they were talking, the bell rang. 他们正在谈话的时候门铃响了。 while “It ＋be(not)＋一段时间＋before...”结构的肯定句意为“多长时间后才……”；否定句意为“用不了多长时间就……”。 It will be a long time before we buy a house. 我们需要很长时间才能买一栋房子。 It was not long before the thief was caught. 不久小偷就被抓住了。 意为“在……之前；……之后才；没来得及……就……”，常表示主句动作先于从句动作发生。从句一般不为否定句。 I must finish this letter before I go home. 我必须在回家之前写完这封信。 She died before she wrote a will. 她还没来得及写遗嘱就去世了。 before 主句是否定句时，谓语须用非延续性动词，表示主句动作直到until/till所表示的时间才发生。 He didnt know anything about it until I told him. 直到我告诉他，他才知道这件事。 意为“直到……”，两者常可互换。主句为肯定句时，谓语须用延续性动词，表示动作一直持续到until所表示的时间为止。 I will wait until/till the concert is over. 我会一直等到音乐会结束。 He stayed there until his teacher came back. 他在那里一直待到他老师回来。 until/till 从句谓语是终止性动词，表示从这一动作开始。 He has written to me frequently since he went abroad. 自从出国以来他经常给我写信。 从句谓语是延续性动词，表示从这一状态的终止开始。 He has written to me frequently since he was ill. 自从病好以来他经常给我写信。　 意为“自从……以来”。主句用完成时，从句常用一般过去时　 since 意为“到某一时间点为止”，主句常用完成时态。 By the time he graduated, he had done many kinds of jobs. 大学毕业之前，他已经做过很多种工作。 by the time 意为“一旦”，暗含条件意味。 Once you begin, you will never give up. 一旦你开始了，就不会放弃。 once 表示显然的或已为人知的理由，语气比because弱，通常置于句首。 Since you wont help me，I will ask someone else. 既然你不肯帮我，我就去问别人了。 since 表示造成某种情况的直接原因。语气最强，常用来回答why的提问。 He didnt have breakfast because he got up too late. 因为起床太晚了，他没有吃早饭。 because 用法 引导词 意为“既然”，表示微弱的原因，位于句首时，that可省略。 Now (that) you understand, I dont need to explain again. 既然你已经明白了，我没有必要再解释一遍。 now that 表示的原因是已知的事实或显而易见的原因，语气比since