现在完成时现在完成时（present perfect tense）通常表示过去发生的动作一直延续到现在，而且还可能继续下去，或者表示过去的行为对现在造成一定的影响，可能还会产生结果等。
1.现在完成时结构1.1.助动词have/has+动词过去分词。
其中，助动词要随着主语的变化而变化，当主语是第三人称单数时，助动词要用“has”。
例：Have you finished your work?He says that he has seen UFOs many times.1.2.现在完成时的缩写形式：I have=I ’ve have not= haven’thas not= hasn’t例：I’ve finished my work./He hasn’t finished his work.1.3.现在完成时的一般疑问句：Have/Has+主语+动词的过去分词+其他？肯定回答：Yes,主语+have/has.否定回答：No,主语+haven’t/hasn’t.例：----Have you finished your work?----Yes,I have./No,l haven’t.----Have they arrived?----Yes,they have./No,they haven’t. 1.4.1.通过加-ed的形式来构成规则动词的过去分词，就像我们构成这些动词的过去式方法一样。
大多数动词后+ed.如finish---finished.以字母e为结尾的动词后+d,如change---changed.以辅音字母加y结尾的动词，去掉y,再加ied.如carry---carried.以一个元音再加一个辅音结尾的短动词，双写辅音辅音字母再加ed.如stop---stopped1.4.2.构成不规则动词的过去分词的方法有所不同，需要特别记忆。
如：come---come; hurt---hurt. lend---lent; build---builtcatch---caught; keep---kept forget---forgotten tell---toldbe---been; have---had fall---fallen; fly---flowndraw---drawn; see---seen；think---thought.2.现在完成时的用法2.1.表示过去发生或已经完成的动作，对现在造成的影响或结果。
通常与表示时间的词汇连用，常见的有“already, yet, ever, just, recently, since, for. lately”Justin has disappeared for three days, so Kelly is very sad.I have just finished my homework.2.2.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(包括现在)的一段状语连用，如“for，since, so far, now, today, this week, this month”。
如：She has lived in Beijing since she moved in China.I have known her for a long time.2.3.一般现在时可用于重复的行为中,表示到现在为止这一段时间内，多次动作总和或所做过的工作量的积累。
如：I have been to Shanghai twice.I have mopped the floor three times today.3.注意现在完成时和一般过去时的区别。
现在完成时表示到说话时为止已经发生或完成的动作或状态，强调造成的结果或对现在的影响；而一般过去时侧重于陈述过去发生的事情或状态，与现在没关系。
例：He has just been to British and saw the Big Ben there.经常与一般过去时连用的表示时间的词语有“yesterday ,theother day, last…, ago…”;与现在完成时常用的表示时间的词语有“already, ever, just, recently （not）yet, since等。
”例：He went to Beijing two years ago.（一般过去时）He has already lived in Beijing for two years.（现在进行时）练习：用现在完成时和一般过去时完成下列句子1.We ____（go）to the park last month.2.___you ever ___（try）the famous Beijing Duck?3.I am happy that I___（learn）to swim.4.I ___ （visit）the Great Wall with my parents the other day.4.现在完成时中have/has been 和have/has gone的用法。
have/has been t o用来表达某人去了一个地方并且已经回来了，指的是一次经历；have/has gone用来表达某人去了一个地方，但是还没回来。
例:Millie and Amy have been to the South Hill and they want to go there again.（米莉和艾米去过南山，而且她们还想再去那里）Millie and Amy have gone to the South Hill and they will come back tomorrow.（米莉和艾米去了南山，她们将明天回来。
）练习：用have/has been 或have/has gone 填空。
1.Sandy isn’t here,she___to the library.2.I ___just___to the library and borrowed some interesting books.3.My cousin ___to Xi’an twice.4.My cousin ___to Xi’an and he will stay there for a week.5.与for和since连用的动词现在完成时常与for或since等引导的表示一段时间的状连用.如for ten minutes,since 1985等.“for+时间段”强调这一段时间的长度。
“since+时间点（或一个从句）”强调这一段时间的起点。
（1）.在现在完成时的肯定句中，和for与since连用的谓语动词要用延续性动词，如work,be,study,liveHe has studied English since two years ago.（2）.某些非延续性动词的否定形式可以与for或since等时间状语连用。
Haven’t seen you for a long time.（3）一些延续性动词和非延续性动词的转换现在完成时综合练习1.（）----Have you eaten my food,Andy?---- No,I ___.A.haveB.haven’tC.hasD.has’t2.（）Our country ___ a lot since 1978. Now, it’s much stronger.A.is changedB.changedC.has changedD.changes3.（）I ___ her for many years, so I can’t remember her name.A.haven’t seenB.have seenC.didn’t seeD.see4.（）Simon has ___fed the dog, but he hasn’t watered the plants.A.still,alreadyB.yet,alreadyC.yet,stillD.already,yet5.（）----Why doesn’t Tony come?----The invitation letter ___to Toby by accident.A.was emailedB.has emailedC.is emailedD.emailed6.（）----Mom,I want to watch T he Legend of Miyue on channal 8 tonight.----Oh,dear, it ___for a few e on!A.has begunB.will beginC.has been onD.will be on7.（）----Peter, you speak Chinese so well.----Thank you.I___Chinese since I came here in 2013.A.will learnB.learnedC.have learnedD.learn8.（）----What a nice watch!How long ___ you ___ it?----For just two weeks.A.will,buyB.have,hadC.were,havingD.did,buy9.（）----Will you watch the programme Running Man in Zhejiang Satellite-TV tonight.----Yes, of course.It＿＿one of the most popular shows since last October.A.wasB.becameC.has beenD.has become10.（）----What age did you leave home?---- I left home at 18,Neil. I___ your city for five years.A.have gone toB.have been toC.have been inD.have come to11.（）Mike used to be a top student,but he _____behind since he lost himself in computer games.A.fellB.has fallenC.wasD.has been12.（）-----______you _____Jeremy Shu-How Lin?-----Yes.The once nameless young man became a basketball hero suddenly.A.Did,hearB.Do,listen toC.Have, heard ofD.Have,listen to。