Present perfect simple

Present perfect simple

Form

Positive statement: I have cooked, I have written , He has cooked, He has written (I've cooked, He's cooked)
Negative statement: I have not played (I haven't played), He has not done (He hasn't done)
Question: Have you worked?
Negative question: Have you not bought? (Haven't you bought?)

This tense is made with the present simple form of the verb to have (have, has) and the past participle (cooked, written). It is similar to other perfect tenses.

Use

1. We use the present perfect simple for activities or states that started in the past and still continue.

We have lived here since 2001.
She has known me for more than two years.
I haven't seen her since Christmas.
How long have they been here?

It is often used with expressions indicating that the activities come up to now, such as: for 10 years, since 1995, all week, all the time, always, lately, recently ...
We have always worked in York. (We still work in York.)
It has been quite cold lately. (It is still cold.)

If the activity started and ended in the past we cannot use the present perfect.
I have smoked for 5 years. (= I still smoke.)
I smoked for 5 years. (= I smoked, for example, from 2000 to 2005, then I stopped.)

2. We use it to describe some experience that happened in the past (the time is not given), but the effects are important now.
She has been to London. (And so she knows London.)

Compare:
I have already been to Greece. (experience - And I want to go somewhere else now.)
I have been in Greece for two weeks. (state - I am stlill in Greece.)

When we use this tense to express some experience, we can use following adverbs - ever, never, already, often, occassionaly, yet, before ......
Have you ever tried it?
She has never read this book.
We haven't seen it yet.
Have you fallen off a bike yet?
I haven't met her before.

3. The present perfect simple is used for activities that have a present result.
The bus hasn't arrived. (It did not arrived on time and we are still waiting now.)
I have bought a new house. (I did it last month and it means that now I have a new address.)

For such activities we often use these adverbs - yet, already, just.
They haven't finished their homework yet. (They can't go out now.)
Has she signed it yet? (Can I take the document?)
I've already sent the letter. (There is no need to go to the post-office.)
We have just heard the news. (We know about it.)