1. Present Perfect

2. Present Perfect - Form
The present perfect of any verb is composed of two elements : the appropriate form of the auxiliary verb to have (present tense), plus the past participle of the main verb.

3. Present Perfect - Form
The past participle of a regular verb is base+ed, e.g. played, arrived, looked. For irregular verbs, see the Table of irregular verbs in the section called 'Verbs'.

4. Affirmative
Subject to have past participle
She has visited

5. Negative
Subject to have + not past participle
She hasn't visited

6. Interrogative
to have subject past participle
Has she visited?

7. Interrogative negative
to have + not subject past participle
Hasn't she visited...?

8. Present perfect, function
The Present Perfect is used to indicate a link between the present and the past. The time of the action is before now but not specified, and we are often more interested in the result than in the action itself.

9. USES The Present Perfect is used to describe:
An action or situation that started in the past and continues in the present. Example: I have lived in Bristol since 1984 (= and I still do.)
An action performed during a period that has not yet finished. Example: She has been to the cinema twice this week (= and the week isn't over yet.)

10. USES
A repeated action in an unspecified period between the past and now. Example: We have visited Portugal several times.
An action that was completed in the very recent past, (expressed by 'just'). Example: I have just finished my work.
An action when the time is not important. Example: He has read 'War and Peace'. (the result of his reading is important)

11. Note: When we want to give or ask details about when, where, who, we use the simple past. Example: He read 'War and Peace' last week.

12. Examples:
1. Actions started in the past and continuing in the present.
They haven't lived here for years.
She has worked in the bank for five years.
We have had the same car for ten years.
Have you played the piano since you were a child?
2. When the time period referred to has not finished.
I have worked hard this week.
It has rained a lot this year.
We haven't seen her today.

13. EXAMPLES
3. Actions repeated in an unspecified period between the past and now.
They have seen that film six times.
It has happened several times already.
She has visited them frequently.
We have eaten at that restaurant many times.
4. Actions completed in the very recent past (+just).
Have you just finished work?
I have just eaten.
We have just seen her.
Has he just left?
5. When the precise time of the action is not important or not known.
Someone has eaten my soup!
Have you seen 'Gone with the Wind'?
She's studied Japanese, Russian and English.

14. Present perfect + ever,never,already,yet
The adverbs ever and never express the idea of an unidentified time before now e.g. Have you ever visited Berlin?

15. 'Ever' is used
in questions. e.g. Have you ever been to England? Has she ever met the Prime Minister?
in negative questions e.g. Haven't they ever been to Europe? Haven't you ever eaten Chinese food?
and in negative statements using the pattern nothing ever, nobody ever e.g. Nobody has ever said that to me before. Nothing like this has ever happened to us.
'Ever' is also used with 'The first time.... e.g. It's the first time (that) I've ever eaten snails. This is the first time I've ever been to England.

16. NEVER
'Never' means at no time before now, and is the same as not ever:
I have never visited Berlin
BE CAREFUL!
You must not use never and not together:
I haven't never been to Italy.
I have never been to Italy.

17. Position
Ever' and 'never' are always placed before the main verb (past participle).

18. Already
refers to an action that has happened at an unspecified time before now. It suggests that there is no need for repetition, e.g. a. I've already drunk three coffees this morning. (and you're offering me another one!) b. Don't write to John, I've already done it.
It is also used in questions:
Have you already written to John?
Has she finished her homework already?

19. POSITION
already can be placed before the main verb (past participle) or at the end of the sentence:
I have already been to Tokyo.
I have been to Tokyo already.

20. YET
is used in negative statements and questions, to mean (not) in the period of time between before now and now, (not) up to and including the present. e.g.
Have you met Judy yet?
I haven't visited the Tate Gallery yet.
Has he arrived yet?
They haven't eaten yet.

21. Yet is usually placed at the end of the sentence.
Position
Yet is usually placed at the end of the sentence.

22. Present Perfect of Simple Past?
How to choose between the Present Perfect and Simple Past Tenses
Always use the Present Perfect when the time is not important, or not specified.
Always use the Simple Past when details about the time or place are specified or asked for

23. Present Perfect Simple Past
I have lived in Lyon I lived in Lyon in 1989.
They have eaten Thai food They ate Thai food last night.
Have you seen 'Othello'? Where did you see 'Othello'?
We have been to Ireland When did you go to Ireland?
There is also a difference of attitude that is often more important than the time factor.
"What did you do at school today?" is a question about activities, and considers the school day as finished.
"What have you done at school today?" is a question about results - "show me", and regards the time of speaking as a continuation of the school day.

24. Present Perfect + for and since
Using the present perfect, we can define a period of time before now by considering its duration, with for + a period of time, or by considering its starting point, with since + a point in time

25. For + a period of time
for six years, for a week, for a month, for hours, for two hours.
I have worked here for five years.

26. Since + a point in time
since this morning, since last week, since yesterday,
since I was a child, since Wednesday, since 2 o'clock.
I have worked here since 1990.

27. present perfect with for
She has lived here for twenty years.
We have taught at this school for a long time.
Alice has been married for three months.
They have been at the hotel for a week.

28. present perfect with since
She has lived here since 1980.
We have taught at this school since 1965
Alice has been married since March 2nd.
They have been at the hotel since last Tuesday.

29. NOTE For and since can both be used with the past perfect.
Since can only be used with perfect tenses, for can also be used with the simple past.

30. THAT´S ALL FOLKS