1.共同点：
现在完成时和一般过去时都表示一个在过去完成的动作。
2.区别：
①现在完成时强调的是与现在的关系，如对现在产生的结果或影响等，属于现在时范围，谈论的是现在的情况。而一般过去时只表示动作在过去某一时刻发生，不表示和现在的关系，现在情况可能已发生变化。
Who opened the door? (谁开的门？只强调过去开门这一动作，门现在可能已关上。)
Who has opened the door? (谁把门开了？强调门现在依然还开着。)
②现在完成时不能与明确的过去时间状语连用，如：three days ago, last year, yesterday, last Sunday, in2008等等。如句中有以上这些明确的过去时间状语，应用一般过去时。再有，过去发生的一个动作，如现在情况已经发生的变化，也应用一般过去时。
☆特别提醒：如果这些过去时间状语前有since，表示自过去某一时间一直延续到现在，应用现在完成时。
He finished reading the book the day before yesterday.
I put my ruler in my pencil-box, but I cant find it now.
My cousin has been in Nanjing since 2009.
③现在完成时不与when引导的特殊疑问句连用，when后只用一般过去时表示已发生的动作。但现在完成时可与where, why等疑问词连用。如：Where have you been? (你去过哪里了？)
--The train has left.
--When did the train leave?
④since引导的时间状语从句后面用一般过去时，只有前面的主句才用现在完成时。
We have known each other since we came to the school two years ago.
⑤有些时间状语，如this morning, this month, tonight等，既可以与一般过去时连用，又可以与现在完成时连用，但内涵不同。与一般过去时连用时，表示与现在无关，时间已成为过去。而与现在完成时连用，则表示包括现在在内。
I saw him this morning. (时间已不在上午了。)
I have seen him this morning. (说话时间还是上午。)
He lived in New York for eight years. (他现在已经不在纽约住了。)
He has lived in New York for eight years. (他现在还在纽约居住。)
同步练习
动词填空：
1. I ______(see)Tom last Friday.
2. _____you _____(go)to the Great Wall last summer?
3.--Where _____you _____(put) my pen?
--I ______(put) it in my pencil-box, but its nowhere to be found.
4.When ______you______(start) to live in China?
5.--The train______ (leave) already.
--When ______ the train ______(leave)?
6.It is five years since I ______(meet) you last.
7.Where _____ you_____(be) for the last two weeks?
8.I _____ (lose)my pen in the bedroom. I have to write with a pencil.
单项选择：
( ) 1. --Where ____ the recorder? I cant see it anywhere.
-- I _____ it right here. But now its gone!
A.did you put; have put
B. have you put;put
C. had you put; was putting
D. were you putting; have put
( ) 2. My father _____ here since he _____ to this school.
A. taught; came
B.has taught; came
C. taught; has come
D. has taught; has come
( ) 3. I am sorry youve missed the train. It_____ 10 minutes ago. (山东)
A. left B. has left
C. has been left D.had left
( ) 4. Hi! Jim! Nice to meet you again! Its one year since I last _____ you.(重庆)
A. saw B. see
C. seeing D. have seen
( ) 5. -- Have you visited the Dinosaur World,Elsa? （宁波）
-- Yes, I ____ it yesterday.
A. have visited B. had visited
C. visited D. visit
( ) 6. -- Nice to see you. I _____ you for along time. (南京)
-- I _____ in Bejing. Ive just come back.
A. hadnt seen; am
B. havent seen; was
C. didnt see; will be
D. havent seen; shall be
( ) 7. --What is the weather like this summer here?
-- There ____ very little rain.
A. has B. has been
C. are D. have been
( ) 8. When ____you ____ your dictionary?
A. did; lose B. has; lost
C. will; lose D. does; lose
( ) 9. Where ____ you _____? Which answer is not right?
A. are; going B. have; been
C. did; go D.are; doing
( ) 10. There ____ many great changes in my hometown since ten years ago.
A. were B. have
C. are D. have been
Keys:
动词填空：
1. saw 2. Did, go 3. have, put, put
4. did,start 5. has left, did, leave
6. met 7. have, been
8. have lost
单项选择：
1~5 BBAAC 6~10 BBADD
