Present Perfect

Use
We use the present perfect tense:

when we talk about our experience up to the present:

I’ve read all of the Harry Potter books.

Note: We often use the adverb ever to talk about experience up to the present:

My last birthday was the worst day I have ever had.

Note: and we use never for the negative form:

Have you ever met George?Yes, but I’ve never met his wife.
we often use the present perfect for recent events (just; only just; recently)
I’ve just seen Peter in town.
Scientists have recently discovered a new breed of monkey.
We have just got back from our holidays.

A past action with a result in the present.

I have lost my keys. ( And now i can’t get into my house)
for something that started in the past and continues in the present:
They’ve been married for nearly fifty years.
She has lived in Liverpool all her life.

BEEN and GONE
We use the present perfect of be when someone has gone to a place and returned:
A: Where have you been?B: I’ve just been out to the supermarket. (I’m back now)
A: Have you ever been to San Francisco?B: No, but I’ve been to Los Angeles.
But when someone has not returned we use have/has gone:
A: Where is Maria? I haven’t seen her for weeks.B: She’s gone to Paris for a week. She’ll be back tomorrow. (she’s still in Paris)

PRESENT PERFECT vs PAST SIMPLE

WARNING:
We do not use the present perfect with a time reference which refers to past time which is finished:
I have seen that film yesterday.We have just bought a new car last week.When we were children we have been to California.
But we can use it to refer to a time which is not yet finished: