still don't understand "present perfect

[endeavor6636]

(press the picture to zoom)

as the picture showns, "have done" mean to talk about something happened between the past and present. (but "past" could mean last year, 2 years ago,
or even 1 min before now could called "past" ) if you said " i have lost my key" it means lost your key between the past and now. if "past" mean two years ago, the key could be lost 1 year after the "past "

i have lost my key ????? i lost my key ?????
( so , when you lost your key ? 1 year ago? becasue in my mind i am thinking about "2 year ago as "past", now is "presesnt", the key could be lost anytime between 2 years ago and now.) I am very confuse

[DavyBCN]

Originally Posted by endeavor6636

(press the picture to zoom)
as the picture showns, "have done" mean to talk about something happened between the past and present. (but "past" could mean last year, 2 years ago,
or even 1 min before now could called "past" ) if you said " i have lost my key" it means lost your key between the past and now. if "past" mean two years ago, the key could be lost 1 year after the "past "
i have lost my key ????? i lost my key ?????
( so , when you lost your key ? 1 year ago? becasue in my mind i am thinking about "2 year ago as "past", now is "presesnt", the key could be lost anytime between 2 years ago and now.) I am very confuse

You are not the only person to be confused by the present perfect. It is used more or less in the same way in English and Spanish, but there are some differences which make it the one thing English teachers here hate to teach!

The diagram is ok, but does not really tell you "how" to use the present perfect. The explanation my students seem to be happier with is that this is the tense we use to talk about 1) experiences or actions which have happened "up to now", and 2) experiences or actions which happened at some time in the past but which "have an effect on" the present. It is also important to remember that tense and time are not necessarily the same thing. I really believe very strongly that the best way to understand the present perfect tense is to find as many examples of it being used as possible.

Some examples on 1) above:-

I have visited Madrid. This happened at some time in the past. I may have visited Madrid many times or just once. The important thing is I use the present perfect tense because I am saying that I have visited Madrid in the past but that does not mean I will not visit Madrid again. So I am talking about up to now in my life. If I used the past simple tense "I went to Madrid" then I am usually saying I visited Madrid and consider that as a single action in the past. It makes it easier to understand if you relate both examples to the time expressions you mentioned. I have visited Madrid 10 times (in my life up to now); I visited Madrid 10 times in 2003.

Other examples:- I have studied English for 6 years (up to now in my life); I studied English for 6 years (I am not studying English now). I have lived in Barcelona for 3 years (up to now); I lived in Barcelona for 3 years (now I live somewhere else).

Your example of the lost key is a good one for the second use of the present perfect I mentioned above. If you used the past perfect "I lost my key", then it is a single action which happened in the past and is finished. You could use a time reference like last year/yesterday/in 1997. If you use the present prefect "I have lost my key", then it is something that happened in the past, but you could not use the same time expressions (probably because you do not know when you lost it), and the loss of the key has an effect in the present - "so how am I going to get into my house!?"

I hope this helps - but experience suggest it may just confuse you more. The best way really is to search for grammar sites which give as many examples of the similar sentences using both past simple and present perfect so the meaning becomes easier. Good luck!

[rewboss]

In the simplest terms: the present perfect links the past with the present. Does that help a little bit?

[endeavor6636]

what about) am i right about the meaning

you have grown ( from last time i saw u to now , you have grown, and you might grow taller in the future.)

you grew( you grew , you are no longer grow any taller.)

[isko_sbma]

i like your explanationation about the present perfect tense. it cleared some of my problems in using the perfect tenses. please i would like to ask for the same explanation on the use of past perfect tense and future perfest tense.

thank you in advance.

[DavyBCN]

Originally Posted by endeavor6636

what about) am i right about the meaning
you have grown ( from last time i saw u to now , you have grown, and you might grow taller in the future.)
you grew( you grew , you are no longer grow any taller.)

Perfect. Unfortunately, the verb you used does lead to another complication . British English speakers (like me) use the present perfect in exactly this way. American English speakers will often use the past simple to say the same thing. Look at this short dialogue:-

John: I'm hungry, Shall we have lunch?
Brit: I'm not hungry because I've already eaten.
Yank: I'm not hungry because I already ate.

Not surprising English learners have a problem

[DavyBCN]

Originally Posted by isko_sbma

i like your explanationation about the present perfect tense. it cleared some of my problems in using the perfect tenses. please i would like to ask for the same explanation on the use of past perfect tense and future perfest tense.
thank you in advance.

Happy to help, but will have to be later today. With any luck someone else will explain as it could take a little time

[endeavor6636]

first let me say thank you very much Davy for clarify that for me and also your suggestion
there is 3 more sentence i would like you to help me check.
1.Since computers were first introduced to the public in the early 1980's, technology has changed a great deal.

2.Computers have become powerful machines with very practical applications.

3.I think you're right. He has walked by us at least twenty times. He probably thinks we have already ordered.

4.John has been working for the government since he graduated from Harvard University. Until recently, he has enjoyed his work, but now he is talking about retiring.

(just want to make sure if i was correct about the interpretation of the sentences)


#1.since the pc was made to the present, technology has changed a great deal between that period of time."

#2.from the time when the computers were first made to the present, "pc have become powerful machines" <<< happened between that period of time.)
#3. from the time they arrived the resturant to now , between that period of time, the waiter have walked by their table 20 times.
#4.he has enjoyed his job , <<<happened some point between the first day he got the job and the present.





Am i right?

[DavyBCN]

Originally Posted by endeavor6636

first let me say thank you very much Davy for clarify that for me and also your suggestion
there is 3 more sentence i would like you to help me check.
1.Since computers were first introduced to the public in the early 1980's, technology has changed a great deal.
2.Computers have become powerful machines with very practical applications.
3.I think you're right. He has walked by us at least twenty times. He probably thinks we have already ordered.
4.John has been working for the government since he graduated from Harvard University. Until recently, he has enjoyed his work, but now he is talking about retiring.
(just want to make sure if i was correct about the interpretation of the sentences)
#1.since the pc was made to the present, technology has changed a great deal between that period of time."
#2.from the time when the computers were first made to the present, "pc have become powerful machines" <<< happened between that period of time.)
#3. from the time they arrived the resturant to now , between that period of time, the waiter have walked by their table 20 times.
#4.he has enjoyed his job , <<<happened some point between the first day he got the job and the present.
Am i right?

Yes - but instead of using the phrase "between that period of time" I would say "from a time in the past up to now" - or perhaps "during that period of time". I think you have understood the concept, but to say "between" might confuse you with other grammar - or maybe not. Sometimes whatever phrase each of us uses is less important than the fact that we understand - which I think you do now.

[matilda]

present perfect is s.th that is done in the past and it is finished now. it means that there is nothing left for you to do but the effect is still visible.