Unit 3 Period Three（课件）-2018版步步高学案导学与随堂笔记英语（人教版必修2）全国版

Unit 3　Computers 写作专题 内容索引 Period Three　Grammar & Writing 语法专题 语法专题 Ⅰ.用所给词的正确形式完成课文原句 1.Over time I (change) quite a lot. 2.First as a PC (personal computer) and then as a laptop，I _________ ____(use) in offices and homes since the 1970s. 3.Over time my memory has developed so much that，like an elephant，I never forget anything I (tell)! 语法感知 现在完成时的被动语态 have been changed have been used have been told 4.Since the 1970s many new applications (find) for me. 5.I also (put) into robots and used to make mobile phones as well as help with medical operations. have been found have been put Ⅱ.用所给动词的正确形式填空 1.This part of the seabed (explore) many times. 2.Much useful information about these planets (collect) since 1971. 3.How many suggestions (give) to you so far? 4.The temple (repair) since last year. 5.A piano concert (give) here last Friday. 6.The problem (solve) up to now. has been explored has been collected have been given has been repaired was given has been solved 现在完成时的被动语态表示到现在为止某事已经被完成或被做。这种语法项目既要表示现在已经完成又要表示被动的含义，因此很多同学在具体运用当中容易顾此失彼，难以把握。 运用现在完成时的被动语态时应掌握以下几个问题： 1.构成 现在完成时的被动语态的构成为：have/has been＋过去分词。 语法精析 2.各种句式 肯定式 主语＋have/has been done... 否定式 主语＋have/has not been done... 一般疑问式 Have/Has＋主语＋been done...？ 特殊疑问式 疑问词＋have/has＋主语＋been done...？ 3.使用的场合 (1)表示一个被动的动作发生在说话之前，强调对现在造成的影响或结果。常与already，yet，never，recently等副词及时间状语so far，by now，up till now，since...，before...等连用。 Thousands of man­-made satellites have been sent up into space by many countries. 许多国家已经发射了数千颗人造卫星到太空中。 The doctor hasn’t been sent for yet. 还没有派人去请医生。 (2)表示一个被动的动作或状态开始于过去，持续到现在，并可能持续下去，常与for或since引导的时间状语连用，或用于“How long...？”句型中。 The important problem has been discussed for nearly two weeks. 那个重要的问题已经被讨论近两个星期了。 How long has t