高中英语：unit3 amazing people-grammar and usage学案（牛津译林版必修2）

Unit3 Grammar and usage Period One Present perfect tenseTeaching aim:To give a brief introduction to the present perfect tenseTeaching procedures:1 Go over the news story on Page 2 and find the sentences using the present perfect tense. Please explain why the tense is used in these sentences.2 The form of the present perfect tense3 Talk about the uses of the present perfect tenseA We use the present perfect tense to talk about things that happened in the recent past, but are connected to the present.The disappearance of Justin has made Kelly very unhappy. B We also use the present perfect tense to talk about something that started in the past, and is still happening now.I have not seen Justin since last Friday night.C We use the present perfect tense when the exact time of an action is not clear or important. We use it with time expressions such as: already ever for just lately never recently since yet We use already for affirmative statements and yet for negative statements.We use for + a period of time and since + a point in time. D We use the present perfect tense to talk about actions that were completed only a short time ago. In this case, just is used. Pay attention to the position of just.He has just gone out.(=He went out a few minutes ago.)We use the present perfect tense here to tell others that he isn’t here now. I have just heard the news.(Now I know the news.)E We can also use the present perfect tense for repeated actions, that is, we use the present perfect tense with the time expressions once/twice/three times…F Actions occurring in an incomplete period might be indicated by today or this morning /afternoon/evening/week/month/year/century or all day/night/week...