M2U1 Grammar and usage,Present perfect tense & Present perfect continuous tense,Revision: translate the following sentences,美国警方现已加紧对一名15岁男孩的搜索。 People in America have stepped up their search for a fifteen-year-old boy. 自从上周五晚我就没有看到贾斯汀了。 I have not seen Justin since last Friday night. 该事件引起了公众的极大兴趣. This incident has received great interest.,Present perfect tense,Present perfect tense现在完成时,结构：has/have + done 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(肯定), yet（否定）, just, lately, recently, never, ever, for(一段时间)， since（时间点）,Present perfect tense现在完成时,“动作完成“ 1. We use present perfect tense to talk about things that happened in the recent past but are connected with the present.（主要为短暂性动词） Justin has disappeared, so Kelly is very sad.,Practice,She_(lose) her bike. She_(lose) her bike yesterday. She_(have) a good education. She_(have) a good education when she was young.,Present perfect tense现在完成时,“动作未完成” 2. We also use the present perfect tense to talk about something that started in the past and is still happening now.（延续性动词或表状态的形容词） I have not seen Justin since last Friday night. 常与since, so far, for, by now, until now, recently等连用。,瞬间性动词如 arrive, join , die, get , come, buy, sell, leave, borrow, marry 等，以及终止性动词如start, begin, finish等，在现在完成时的肯定形式中不能与 “for + 一段时间”的时间状语连用，但可以用在否定句或这些动词对应的状态动词中。为了表述这种意思，我们常用相应的延续性动词have,keep,be等来代替非延续性动词。 I have seen him for a month. I havent seen him for a month.,（错）,(对),Practice,1.The price _recently, but I doubt whether it will remain so. A went down, B will go down C has gone down D was going down 2. In the past few years there _ great changes in Da Miao town. A is B were C have been D will be.,Present perfect tense现在完成时,3.We use the present perfect tense for repeated actions.常与频度副词always, often, never, seldom等连用。 Some willages say that they have seen UFOs many times.,Practice,It _(rain) every day this week. She _always_(walk) to school. I _ never_ (see)such a beautiful bird. I _(go/be) to the Great Wall twice.,现在完成时的几点补充,1.have been (to)与 have gone(to)的区别 have been (to)表示“去过某地现在已经回来了”；have gone (to)表示“去某地了还没有回来”；前者可与once, never, several times等连用，后者不能。 He has gone to Hangzhou. He has been to Hangzhou twice. He has never been to Hangzhou. He has once been to Hangzhou.,现在完成时的几点补充,2. 在时间、条件状语从句中，常用现在完成时代替将来完成时。 Dont get off the bus until it has stopped. Unless you have finished your homework, I wont allow you to watch TV.,Present perfect continuous tense 现在完成进行时,结构：has/have been doing 1. We use the present perfect continuous tense to talk about actions that started in the past and are still continuing. I have not been sleeping well since I returned home.,现在完成进行时,2.We also use the present perfect continuous tense to talk about actions that have just finished but are still connected with the present in some way. Kelly: Sorry, Im late. Have you been waiting long? Mavis: Yes. I have been waiting for an hour.,Now that she is out of a job, Lucy _going back to school, but she hasnt decided yet. A. had considered B. has been considering C. considered D. is going to consider,Practice,2. Where have you been? We _ for you everywhere . A. look B. were looking C. have been looking D. had been looked 3. I wonder why Jenny _ us recently. We should have heard from her by now. A. hasnt written B. doesnt write C. wont write D. hadnt written,