Grammar and usage(1),Present perfect tense,Revision: translate the following sentences,1.美国警方现已加紧对一名15岁男孩的搜索。 2.自从上周五晚我就没有看到贾斯丁。 3.这次事件引起了公众的极大兴趣。,Police in America have stepped up their search for a fifteen-year-old boy.,I have not seen Justin since last Friday night.,This incident has received great interest of the public.,4. Its happened to me! 5. Detective Sam Peterson, who has taken charge of the case, told journalists 6. So, while we have not dismissed the idea, we are looking into other possibilities as well.,我曾经碰到过。,负责这一案子的侦探桑姆. 彼特逊告诉记者.,所以，尽管我们不排除这一想法，但是我们也在调查其它的可能性。,The Form of Present Perfect Tense The Active Voice:,Summary:,The affirmative form (肯定形式) : The negative form (否定形式) : The interrogative form(疑问形式)：,S + have not/has not + done+,Have/Has + S + done +,S + have/has + done +,We _(already open) the window. 过去的动作: we opened the window. 对现在的影响: The window is open.,have already opened,How to use present perfect tense?,Situation 1,The boys are tired. They _ (just play) a ball game. 过去的动作 : The boys played a ball game. 对现在的影响: The boys are tired.,have just played,现在完成时表示过去发生的动作对现在产生的影响或结果，或说话时已完成的动作。通常与副词already,yet（已经）just（刚刚）等连用，此时动作的确切时间不明确或不重要。,Summary: 现在完成时用法1-已完成、影响性用法,already:用于肯定句; yet:用于否定句和疑问句,Drill 1,1.Im full . I _(have) lunch already. 2. - Has the train_ (arrive), yet? - Your are early, it _ yet. 3. Doctors _ (find) that people who laugh a lot live longer. So, cheer up! 5. The disappearance of Justin _ (make) Kelly very unhappy.,have had,arrived,have found,hasnt arrived,has made,我的车已经修好了，下周我们可以开车去上海。,My car has been repaired. We can drive to Shanghai next week.,have /has +been +done,The form of Passive Voice:,Daniel _ (live) in Beijing since he came to China.,has lived,came,Situation 2,Summary 2：,强调动作或状态发生于过去一直延续到现在（适用于延续动词）,1. for + 时间段； since + 时间点/ 从句 2. 迄今为止：so far, up till/to now, until now 3.最近的过去：in /during/over the last/past few years(days, weeks, months) 4.最近：recently, lately, . 5.从以来: ever since,常与下列时间短语连用,现在完成时用法2-未完成,延续性,Drill 2,1.The price _（increase）recently, but I doubt whether it will remain so. 2. In the past few years there _(be) great changes in our town.,has increased,have been,( ) 1. He has come here. ( ) 2. He has come here for 3 days. ( ) 3. He hasnt come here for 3 days. ( ) 4. He has stayed here for 3 days. ( ) 5. He has been away for 3 days.,Right or wrong? Why?,Drill 3,终止性动词/ 瞬间动词,动词,延续性动词,arrive, join , die, begin , come, buy, leave, borrow, marry.,be, have, keep, study, live.,瞬间动词的现在完成时的肯定式不能和表示延续的时间状语（for+时间段,since+时间点/从句）连用, 也不能用在how long引导的特殊疑问句中。（但可以用在否定句或这些动词对应的状态动词中）,Tips :,常见终止性动词与延续性动词(或状态动词)的对应关系如下: die-be dead close-be closed become-be leave-be away (from) fall asleep-be asleep borrow-keep begin / start-be on buy-have end / finish-be over marry-be married catch a cold-have a cold join the army-be in the army,Correct the mistakes,His father has died. (for 2 years) The football match has begun.(since9:00a.m) I have bought the computer.(since I graduated),His father has been dead for 2 years.,The football match has been on since 9:00 a.m.,I have had the computer since I graduated.,I went to Egypt in 1986. I went to Egypt in 2004. I _ (be) to Egypt twice.,have been,现在完成时用法3-经历用法,现在完成时表示从过去到现在曾经发生过或经历过某事。常与副词 ever, never, once, twice, before 连用。,Summary:,How many times have you been to Egypt?,have been (to)和have gone (to)的区别： have / has been (to) 表示“曾经去过”某地，说话时此人很可能不在那里，已经回来。侧重指经历。 have / has gone (to) 表示某人“已经去了”某地，说话时此人在那里，或可能在路上，反正不在这里。 He has been to Beijing. (人已回来,可能在这儿) He has gone to Beijing. (人已走, 不在这儿) - Where is the person in charge? - The person in charge _ to London.,has gone,Sentence patterns : 1) It is (has been) +一段时间 since +从句（一般过去） Its/ It _ 3 years since he joined the army. 2)This (That/It) is the first (second) time + that-clause（从句用现在完成时） This is the first time that I _ (see) pandas 3)This (That/It) is the + 最高级+名词+ that-clause （从句用现在完成时） It is the most delicious food that I _(taste),have seen,have tasted,Extension,has been,在时间或条件状语从句中，现在完成时可以代替将来完成时,表示将来某个时刻之前已经完成的动作,I shall post the letter as soon as I have finished it. 我一写完这封信就寄出去。 Dont get off the bus until it has stopped. 直到车停稳后才能下车。 _， you will realize the theory. 如果你做完这个实验，你对这个理论认识得会更深刻。,If you have done the experiment,Make some sentences using the present perfect tense and simple past tense.,Competition,Put the following sentences into English. A: 火车已经开走了. B: 什么时候开走的? A: 半个小时之前开走的. A: 这本书我已经买了两年了. B: 你在哪儿买的? A: 在我老家买的.,A: The train has left.,B: When did it leave?,A: It left half an hour ago.,A: Ive had the book for 2 years. B: Where did you buy it? A: I bought it in my hometown.,一般过去时与现在完成时的区分 时间上有差异：凡有具体的过去时间，均用过去时态