Unit 3 The Internet Period 3 Discovering Useful Structures 课件-高一英语同步精品课堂(人教版新教材必修第二册)

Period 3 Discovering Useful Structures 1 Discovering Useful Structures Grammar Passive Voice of Present Perfect Tense 2 Discovering Useful Structures My room has been cleaned up. My face has been washed. 3 Discovering Useful Structures My car has been repaired. 4 Discovering Useful Structures Why do we use passive sentences? A pair of active sentence and passsive sentence convey a similar meaning, but they are slightly different. Passive sentences are default and are used often. We use passive sentences when 1. the doer of an action is not necessarily mentioned. 2. the doer of an action is unknown. 3. the doer of an action is not important 4. the doer of an action is preferred not named 5 Discovering Useful Structures What's the structure of passive voice of prsent perfect tense Affirmative form: 主语+have/has been + 过去分词 Negative form: 主语+haven't/hasn't been + 过去分词 Question form: Have/Has +主语+ been + 过去分词 Wh-question +have/has +主语+been+过去分词 6 Discoveri