Present perfect

To clearify that something started in the past, but hasn't ended yet, use the present perfect.
The present perfect consists of: have/has + a past participle.

A past participle of a regular verb is formed by adding '-ed' after the verb.
The past participles of the irregular verbs have their own form that you have to memorize/study.

Examples

I have played the piano for five years.
Simon has lived in Amsterdam since 2001.

If you want to say that something happened in the past and the result is still noticeable, use the present perfect. The time when it happened is not important and not mentioned..

I have lost my keys.
He has already paid for it.
She has heard that story.

You also use 'have' or 'has' + the past participle in question and negative sentences.

	Question	Negative sentence
I have lived.	have I lived?	I haven't lived
You have lived.	Have you lived?	You haven't lived.
He has lived.	Has he lived?	He hasn't lived.
We have lived.	Have we lived?	We haven't lived.
You have lived.	Have you lived?	You haven't lived.
They have lived.	Have they lived?	They haven't lived.