高中英语Unit 1 Tales of unexplained-Grammar ppt 课件VIP免费

Focus OnePresent perfect tense Go through the passage on Page 2 and underline the sentences using present perfect tense.Key sentences: Police in American have stepped up their search for a fifteen-year-old boy…have/has(not)+past participle•People have shown great interest in his disappearance…•I haven’t seen Justin since. •Some people in Dover also say that they have seen aliens.•Police have not ruled out the possibility that Justin was taken by aliens, but …•…who has taken charge of the case.I didn’t see Justin last Friday night.I don’t see Justin at present.●●last Friday nightpresentI haven’t seen Justin since last Friday night.1. We use the present perfect tense to talk about things that happened in the recent past, but are connected to the present. Eg. The disappearance of Justin has made Kelly very unhappy.2.We also use the present perfect tense to talk about something that started in the past, and is still happening now. Eg.I have not seen Justin since last Friday night.3.We use the present perfect tense to talk about actions that were completed only a short time ago. Eg. The police have just finished searching the area.4.We can also use the present perfect tense for repeated actions.Eg. Some villagers say that they have seen UFOs many times. 5. 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 / yet ; ever / never ; for / since; lately / recently; just for or since?We haven’t seen him for two years.We haven’t seen him since 2003. since+a point in time for + a period of timeEg. I haven’t heard from Tom ______ 2000. We have known each other ______5 years.sinceforalready or...