Second year, Unit one (The world of work) present perfect tense

1. Form: to have (present tense)+ the past participle of the main verb.

Positive
Subject to have past participle
She has finished.
Negative
Subject to have + not past participle
She hasn't finished.
Interrogative positive
to have subject past participle
Has she finished...?
Interrogative negative
to have + not subject past participle
Hasn't she finished...?



Example: to leave (irregular verb), present perfect form

Affirmative Negative Interrogative
I have left I haven't left Have I left?
You have left You haven't left Have you left?
He, she, it has left He, she, it hasn't left Has he,she,it left?
We have left We haven't left Have we left?
You have left You haven't left Have you left?
They have left They haven't left Have they left?



2. Use:
The present perfect is used for a complete action: We are thinking of the result when describing:


EXAMPLES:

1. An action or situation that started in the past and continues in the present.

I have lived in Canada since 1984. (and I still do)

2. An action performed during a period that has not yet finished.

She has been to the doctor twice this week. (and the week isn't over yet)

3. A repeated action in an unspecified period between the past and now.

We have visited London several times.

4. An action that was completed in the very recent past (expressed by 'just')

I have just finished my work.

5. An action when the result is very important but the time is not.

He has seen ‘Harry Potter’.


Present perfect OR past simple?

Very Important: When we want to give or ask details about when, where, who, we use the simple past.

Example: He saw ‘Harry Potter’ last week.

Use the present perfect when the time is not important.
Use the simple past when the time or place is important.

PRESENT PERFECT + for, since

When talking about the length of time (duration), we use the present perfect with for + a period of time.
When talking about a starting point, we use the present perfect with since + a point in time.

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. She has lived here for twenty years. They have been married for six months.

Since + a point in time:

since this morning, since last week, since yesterday,
since I was 12, since Friday, since 6 o'clock.

I have lived here since 1998. They have been married since June. We have been at this school since last year.

F PRESENT PERFECT + adverbs (ever, never, already, yet, still)
'Ever' and 'never' are always placed before the past participle.

'Ever' = sometime before now, is used:

a. in questions
Have you ever been to Canada?
Has she ever met someone famous?

b. in negative questions
Haven't they ever been to Canada?
Haven't you ever eaten Thai food?

c. and in negative statements using the pattern nothing.......ever, nobody.......ever e.g.
Nobody has ever said that to me before.
Nothing like that has ever happened to me.

d. 'Ever' is also used with 'The first time.... e.g.
It's the first time I've ever eaten Thai food.
This is the first time I've ever been to Canada.

'Never' = not ever. Never is used after have/has.
I have never visited London. I’ve never been so sick.



Already, yet and still. It can be placed before the main verb (past participle) or at the end of the sentence.

Already = sooner than expected, is used:

a. I've already heard the story five times.
b. Most people have already gone.

It is also used in questions:

a. Have you already rang Mike?
b. Has he arrived already?

Yet is used in negative statements and questions when we are expecting something to happen and goes at the end of the sentence.

a. Have you bought a ticket yet?
b. I haven't met her yet.
c. Has your course started yet?
d. They haven't arrived yet.

Still = continuing longer than expected. Still is stronger than yet and often expresses surprise that a situation has continued for so long.

a. She isn’t home yet. She’s still at work.
b. I still haven’t found what I’m looking for.
c. I’m still thinking about it.

since

- i haven't seen him since last week.
- i haven't played football since i was on holiday.
- i haven't seen him since last two weeks.
- the last time i saw him was two weeks ago.
- i last saw him two weeks ago.
-it is two weeks since i saw him.