**现在完成时**现在完成时是由助动词have（has）+过去分词构成其否定句在Have/has后加not.一般疑问句把have/has提到主语前.动词的过去分词：规则变化（和过去时一样）不规则变化：不规则变化：am/is-was-beenare-were-beenbegin-began-begunbreak-broke-brokendo-did-donedraw-drew-drawndrink-drank-drunkdrive-drove-driveneat-ate-eatenfall-fell-fallenfly-flew-flownforget-forgot-forgottengive-gave-givengo-went-gonegrow-grew-grownhide-hid-hiddenknow-knew-knownlie-lay-lainride-rode-riddenring-rang-rungshow-showed-shownsee-saw-seensing-sang-sungspeak-spoke-spokentake-took-takencome-came-comerun-ran–runbecome-became-become1。表过去发生的某一动作对现在造成的影响或结果,例如Ihavejustcleanedmyclothes.我刚洗过衣服。（“洗衣服”是发生在过去的动作，对现在造成的结果是“衣服干净了”）Ihavejusthadmybreakfast.(对现在的影响：不饿)通常与表示包括现在在内的时间副词just（刚刚）,already（已经）,before,yet（一般疑问：已经；否定句：还）never,ever等状语连用①Ihaveneverheardofthatbefore.②Haveyoueverriddenahorse?③Shehasalreadyfinishedthework.④Haveyoumilkedthecowyet?Yes,Ihavedonethatalready.⑤I’vejustfinishedmyhomework.⑥Hehasnotcomeyet.2。表示过去已经开始，持续到现在的动作或状态，也可以表示实质可能继续下去的动作或状态。通常和for（段时间）,since（点时间）引导的时间状语连用.以及sofar,bynow,thesedays,inthelasttenyears等连用。Ihavebeenhereforjustovertwoyears.Hehasworkedheresince1989.从1989年，Ihaven’tseenherthesedays.ShehaslearntEnglishfor3years/since3yearsago.Theyhavelivedheresince1990.WhathashappenedtotheUSAinthelast350years?注意点一：现在完成时与一般过去时的用法比较现在完成时表示过去的动作一直延续到现在甚至会继续下去或表示过去的动作对现在造成的影响；一般过去时表示动作发生的时间在过去。现在完成时属于现在时态范围，因此，不能和表示过去的时间状语连用。如：yesterday,lastnight,twoweeksago等试比较：Theplanehasarrived.飞机已经来了。（说明现在的情况：飞机在这儿）Theplanearrivedaquarterago.飞机是一刻中以前来的。（强调动作发生的时间在过去）Ihavetaughthereforfifteenyears.我在这儿已经教了十五年。（表示十五年前的动作一直延续到现在，还可能会继续。）Itaughthereforayear.我过去在这儿教过一年。（表示“我“现在已经不在这儿任教了）PutthefollowingsentencesintoEnglish.1.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.2.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.3.A:你看过这部电影吗?B:看过.A:什么时候看的.B:上周星期天看的.A:Thetrainhasleft.B:Whendiditleave.A:Itlefthalfanhourago.A:haveyouseenthefilm?B:Yes,Ihave.A:Whendidyouseeit?B:IsawitlastSunday.A:I`vehadthebookfortwoyears.B:Wheredidyoubuyit?A:Iboughtitinmyhometown.注意点二、非延续性动词与现在完成时短暂性动词在肯定句、疑问句中不能与时间段连用，这些动词是：become,begin,buy,borrow,arrive,come,die,fall,finish,gettoknow,go,join,leave,marry等。为了表述这种意思，我们常用相应的延续性动词have，keep等来代替非延续性动词。他入党五年了。HejoinedthePartyfiveyearsago.——HehasbeeninthePartyforfiveyears.——HehasbeenaPartymemberforfiveyears.——itisfiveyearssincehejoinedtheParty电影开始五分钟了。Thefilmbeganfiveminutesago.——Thefilmhasbeenonforfiveminutes.——Itisfiveminutessincethefilmbegan瞬间动词与延续性动词的转换come/go—be(in)leave—beawayborrow—keepbuy—havedie—bedeadgettoknow—knowbegin—beongoout—beoffgoout—beoffarrive–behere/theremarry/getmarried(to)—bemarried(to)begintowork/study/live–work/study/leavefallasleep/gettosleep—beasleepjointheParty—beintheParty/beamemb...
