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1、Unit 1 Tales of the unexplained,Grammar and usagePresent perfect tense,现在完成时,现在完成时用来表示之前已发生或完成的动作或状态，其结果的确和现在有联系。动作或状态发生在过去但它的影响现在还存在；也可表示持续到现在的动作或状态。其构成：主动式:have/has done被动式:have/has been done,现在完成时的用法：1）表示过去发生或已经完成的某一动作对现在造成的影响或结果。通常与表示包括现在在内的时间副词just，already,before,yet,never,ever等状语连用。例如：I have n
2、ever heard of that before.Have you ever ridden a horse?Ive just lost my science book.,2）表示过去已经开始，持续到现在,也许还会持续下去的动作或状态。可以和表示从过去某一时刻延续到现在的一段时间的状语连用。如：for和since，so far,now,today,this week(month,year),up to now,until/till,during/over/in the past few years等。,Up to now,the program _ thousands of children
3、who would otherwise have died.A.would save B.saves C.had saved D.has saved,D,注意：表示短暂时间动作的词，如come,go,die,marry,buy等的完成时不能与for,since等表示一段时间的短语连用。3）现在完成时还可以用在时间和条件状语从句中,表示将来某时完成的动作。例如：Ill go to your home when I have finished my homework.If it has stopped snowing in the morning,well go to the park.,4）ha
4、ve 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),5)用于现在完成时的句型,It/This is the first/second time that 在这个结构中的从句部分，用现在完成时。如：It is the first time that
5、 I _(visit)the city.This is the first time I _(hear)him sing.,have visited,have heard,This(That/It)is the only time+that-clause This is+形容词最高级+that在这种结构中，that从句要用现在完成时。如：This is the best film that Ive ever seen.It is the only time that I_(travel)abroad.,have traveled,6)Since 的补充用法It is+时间段+since+从句I
6、t is/has been two years since I left my hometown.b.It was/had been two years since I had left my hometown.,一般过去时与现在完成时的区别,一般过去时表示过去某个时间发生的动作，与具体的过去时间状语连用。现在完成时强调对现在的影响，不与具体过去时间状语连用，但可与ever,never,before,just,already 连用。I finished my homework an hour ago.I have already finished my homework.,I saw this
7、 film yesterday.（强调看的动作发生在过去某个时间）I have seen this film.（强调对现在的影响，即电影的内容已经知道了）,英语动词根据词义可分为两种,一种是延续性的,一种是终止性的。终止性动词(也可称为非延续性动词/瞬间动词),如begin,start,die,buy,leave,come等,表示动作的发生与结束于一瞬间完成,不能再延续,所以它的现在完成时不能和表示延续的时间状语连用,即不能与表示一段时间的状语,for+时间段,since+时间点/从句连用,也不能用在howlong引导的特殊疑问句中。,IveleftShanghaiforthreedays.I
8、vebeenawayfromShanghaiforthreedays.IleftShanghaithreedaysago.Itis/hasbeenthreedayssinceIleftShanghai.,Decide the sentences are true or false.,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:come/go/arrive/get/reach/move-be die-bedead close-beclosed become-be borrow-keep begin/start-beon puton-wear leave-beaway(from)buy
9、-have fallasleep-beasleep end/finish-beover catchacold-haveacold jointhearmy-beinthearmy,Translate these sentences into English.,汤姆回来了。汤姆回来一个多星期了。,Tom has come back.,Tom _ back for over a week.,has been,2.他在1998年买了这辆自行车。他自从来到我们学校就买了这辆自行车。,He bought the bike in 1998.,He _the bike since he came to our
10、 school.,has had,3.上个月我借了这本书。这本书我借了一个月了。,I borrowed the book last month.,I _the book for a month.,have kept,Grammar and usagePresent perfect continuous tense,现在完成进行时,现在完成进行时表示动作从过去某一时间开始,一直延续到现在,可能还要继续下去。现在完成进行时是由“have/has+been+动词的现在分词”构成,现在完成进行时的基本用法:1)在强调指出动作还未结束,还要继续下去。如:Ive been reading this boo
11、k for two hours,but I havent finished it.2)强调动作延续时间的长久或带感情色彩。She has always been working like that.她一贯是这样工作的。,3)现在完成进行时表示过去的动作持续到说话时刚结束。Kelly:Sorry Im late.Have you been waiting long?Mavis:Yes.Ive been waiting for an hour.,现在完成时和现在完成进行时,1)现在完成进行时更强调动作的延续性,它是现在完成时的强调形式。试比较:Weve been living here for t
12、en years.Weve lived here for ten years.我们在这儿已经住了十年了。,2)在不用时间状语的情况下,现在完成进行时表示动作仍在进行，而现在完成时则表示动作在过去已结束。如:The students have been preparing for the exam.(还在进行)学生们一直在准备考试。The students have prepared for the exam.(已经结束)学生们为考试作了准备。,1.-Why do you want to work for our company?-This is the job that I _ for.A.l
13、ooked B.am to look C.had looked D.have been looking2.We _ on this project for four hours.Lets have a rest.A.are working B.have been working C.worked D.had worked,D,B,3.I have to see the doctor because I _ a lot lately.A.have been coughing B.had coughed C.coughed D.cough4.Why,Jack,you look so tired!Well,I _the house and I must finish the work tomorrow.A.was painting B.will be painting C.have painted D.have been painting,A,D,
