现在完成时讲解和练习
I.定义：
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。
2.也可以表示过去已经开始，一直延续到现在的动作或状态
II.
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等表示一段时间的词连用。用来持续的动作或状态或表过去重复的动作，如live，study，be，wait等，常和since（自从）或for（经历）引导的词语连用。
如：I have lived here for more than thirty years.我已在此住了30多年。
III.现在完成时的时间状语
1.ever, never, twice（once…）, so far（到目前为止）, by now, up to now, up to the present , already（肯定句）, yet（否定，疑问句）, just(刚刚), before（以前）, recently（近来）等词连用
2.Since+时间点，since+从句(since he came here), for+时间段，in the past/last few years
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等表示一段时间的词连用。用来持续的动作或状态或表过去重复的动作，如live，study，be，wait等，常和since（自从）或for（经历）引导的词语连用。
说明：already与yet都有“已经”的意思，但already常用于肯定句，并用于句中。yet常用于否定句和疑问句，并用于句末。例如：
I have already finished my homework.
I haven’t finished my homework yet. Have you finished your homework yet?
They have left. (他们已经离开了,也就是说现在他们人不在这里)
I have had my lunch. (我已经吃过午饭了,也就是说我现在不饿)
I can’t find my watch now. I t hink I have already lost it.
注意：1)现在完成时不能单独与过去的时间状语连用, 如yesterday, last week, three years ago 等;
2)不能与when连用
IV.现在完成时的用法
A．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，强调对现在造成的影想或结果）。例如：
The car has arrived.车子来了。（结果：车子已在门口）
Someone has broken the window.有人把窗户打破了。（结果：窗户仍破着）
B. 表示过去已经开始，持续到现在的动作或状态，可以和表示从过去某一时刻延续到现在（包括“现在”在内）的一段时间的状语连用,如for+时间段、since+过去的时间点、疑问词how long等。例如：My uncle has worked at this factory for five years. 我叔叔在这个工厂工作已经五年了。
Mr. Black has lived in China since 2002. 自从2002年Mr. Black 一直住在中国。
How long have you been here? 你来这里多久了？
用相应的延续性动词替换短暂性动词，句中谓语动词用现在完成时，时间状语为“for＋时间段”或“since＋时
间点”。如：
He has been in the Green China for three years.
He has been a member of the Green China for three years.
他加入“绿色中国”已经三年了。
The old man died 4 years ago.---- The old man has been dead for 4 years.
He joined the Party 2 years ago.---- He has been in the Party for 2 years.
I bought the book 5 days ago.---- I have had the book for 5 days.
V.现在完成时态与一般过去时态的区别
1一般过去时表示过去某时发生的动作或单纯叙述过去的事情，强调动作；现在完成时为过去发生的，强调过去的事情对现在的影响，强调的是影响。
I saw this film yesterday.（强调动作发生的时间是yesterday 。）
I have seen this film.（强调对现在的影响，电影的内容已经知道了。）
2一般过去时和表示过去的时间状语连用，如：…ago, last week/...
In 2008, in the past, just now, the day before yesterday, yesterday ...then(那时),that day, one day, once(从前)
现在完成时常和recently（近来），ever, never, twice,so far, by now, up to now, up to the present（到目前为止）, since，for，in the past/last few years , already（肯定句）, yet（否定，疑问句）, just(刚刚), before（以前）连用。现在完成时不与表示过去的时间状语连用。现在完成时可表示持续到现在的动作或状态，动词一般是延续性的，如live, teach, learn, work, study, know.
VI.比较have/has been to、have/has gone to 和have been in
have(has) been to...表示“曾去过某地，已经从那里回来了”，可以和ever、never、twice等连用。have(has) gone to表示“已经去了某地，在去那里的途中或到达那里还没有回来”。have(has) been in 表示“在某地呆多长时间”，常与表示一段时间的状语连用，如：since, for, how long 等
He went to Shanghai last week 上周他去了上海
He has been to Shanghai.
他(曾经)到/去过上海.(但他人现在肯定不是在上海而是回来了)
He has gone to Shanghai.
他已经去上海了.(也许刚动身出发,也许已经到了,也许还在路上,反正他人不在这里)
Mr. Brown has been in Shanghai for three days.
布朗先生来上海已经有三天了
语法练习
单项选择
( )1.The famous writer _____ one new book in the past two year .
Ａ. is writing Ｂ.was writing Ｃ.wrote Ｄ.has written ( )2.Have you met Mr. Li ____？
Ａ. Just Ｂ. ago Ｃ.before Ｄ.a moment ago ( )3.—How long have you ____ here ? —About two months .
Ａ. been Ｂ. gone Ｃ. come Ｄ. arrived ( )4.—Our country ____ a lot so far .
—Yes. I hope it will be even ______ .
Ａ. has changed ; well Ｂ. changed ; good Ｃ. has changed ; better Ｄ. changed; better ( )5.—______ you ___ your homework yet ?—Yes. I _____ it a moment ago.
Ａ.Did; do; finished Ｂ.Have; done; finished
Ｃ.Have; done; have finished Ｄ. will; do; finish
( )6.We ______ Xiao Li since she was a little girl .
Ａ. know Ｂ. had known Ｃ. have known Ｄ. knew
( )7.Harry Potter is a very nice film. I _____ twice.
Ａ. will see Ｂ. have seen Ｃ. saw Ｄ.see
( )8.—These farmers have been to the United States .
—Really? When _____ there ?
Ａ. will they go Ｂ.did they go Ｃ. do they go Ｄ. have they gone ( )9.Zhou Lang ______already ______in this school for two years .
Ａ. was ; studying Ｂ. will ; study Ｃ. has ; studied Ｄ. are; studying ( )10.His father ______ the Party since 1998 .
Ａ.joined Ｂ. has joined Ｃ. was in Ｄ. has been in ( )11.—Do you know him well ? — Sure .We ______ friends since ten years ago .
Ａ. were Ｂ. have been Ｃ. have become Ｄ. have made ( )12.He has ___ been to Shanghai, has he ?
Ａ. already Ｂ.never Ｃ.ever Ｄ. still
( )13.Hurry up! The play __________ for ten minutes .
Ａ. has begun Ｂ. had begun Ｃ. has been on Ｄ. began
( )14.It ___ ten years since he left the army .
Ａ. Is Ｂ. has Ｃ. will Ｄ. was
( )15.Miss Green isn't in the office. She_______ to the library.
Ａ.has gone Ｂ. went Ｃ.will go Ｄ. has been
( )16.My parents ______ Shandong for ten years.
Ａ. have been in Ｂ. have been toＣ. have gone to Ｄ. have been ( )17.The students have cleaned the classroom, ____?
A. so they
B. don’t they
C. have they
D. haven’t they ( )18.has Mr. White been a member of Greener China since heto China?
A. How soon, comes
B. How often, got
C. How long, came
D. How far, arrived
( )19.His uncle for more than 9 years.
A. has come here
B. has started to work
C. has lived there
D. has left the university
( )20.His father ______ the Party since 1978 .
A. joined
B. has joined
C. was in
D. has been in
延续性动词和瞬间性动词之间的转化
1.He died 10 years ago.
——He ______________ for 10 years / since 10 years ago. 2. He borrowed the book 2 weeks ago.
——He _____________the book for 2 weeks.
3. He bought the motorbike a month ago.
——He ___________the motorbike for a month.
4. He arrived here three days ago.
——He ____________here since three days ago.
5. They turned off the light 2 hours ago.
—— The light __________for 2 hours.
6. He left here 2 years ago.
—— He ____________from here for 2 years.
7. The film began 30 minutes ago.
——The film __________ for 30 minutes.
8. They opened the door an hour ago.
—— The door __________ for an hour.
9. They closed the door an hour ago.
——The door ___________for an hour.
10. He joined the army last year.
——He _____________ the army for a year.
——It ___________ a year ____________ he joined the army.