Study this example situation:

Ann is looking for her key. She can’t find it.

Ann is looking for her key. She can’t find it. She has lost her key. - English Grammar - Present Perfect and Past - Part 1
Ann is looking for her key. She can’t find it.

She has lost her key. (present perfect)

This means that she doesn’t have her key now.

 

Twenty minutes later:

Now Ann has found her key. She has it now.

Now Ann has found her key. She has it now. - English Grammar - Present Perfect and Past - Part 1

Has she lost her key? (present perfect)

No, she hasn’t. She has found it.

Did she lose her key? (past simple)

Yes, she did.

She lost her key (past simple)

but now she has found it. (present perfect)

 

The present perfect is a present tense. It always tells us something about now. “Ann has lost her key” = she doesn’t have her key now (see English Grammar – Present Perfect – Part 1).

The past simple tells us only about the past. If somebody says “Ann lost her key”, we don’t know whether she has it now or not. We only know that she lost it at some time in the past.

Two more examples:

  • Paul grew a beard but now he has shaved it off. (so he doesn’t have a beard now)
Paul grew a beard but now he has shaved it off. - English Grammar - Present Perfect and Past - Part 1
Paul grew a beard but now he has shaved it off.

 

  • They went out after lunch and they’ve just come back. (so they are back now)
They went out after lunch and they’ve just come back. - English Grammar - Present Perfect and Past - Part 1
They went out after lunch and they’ve just come back.

 

Do not use the present perfect if there is no connection with the present (for example, things that happened a long time ago):

  • The Chinese invented printing. (not “have invented”)
The Chinese invented printing. - English Grammar - Present Perfect and Past - Part 1
The Chinese invented printing.

 

  • How many plays did Shakespeare write? (not “has Shakespeare written”)
How many plays did Shakespeare write? - English Grammar - Present Perfect and Past - Part 1
How many plays did Shakespeare write?

 

  • Beethoven was a great composer. (not “has been”)
Beethoven was a great composer. - English Grammar - Present Perfect and Past - Part 1
Beethoven was a great composer.

 

Compare:

  • Shakespeare wrote many plays.
Shakespeare wrote many plays. - English Grammar - Present Perfect and Past - Part 1
Shakespeare wrote many plays.

 

  • My sister is a young writer. She has written many books. (she still writes books)
My sister is a young writer. She has written many books. - English Grammar - Present Perfect and Past - Part 1
My sister is a young writer. She has written many books.

 

We use the present perfect to give new information (see English Grammar – Present Perfect – Part 1). But if we continue to talk about it, we normally use the past simple:

Ow! I’ve burnt myself.

How did you do that? (not “have you done”)

I picked up a hot dish. (not “have picked”)

Ow! I’ve burnt myself. How did you do that? I picked up a hot dish. - English Grammar - Present Perfect and Past - Part 1
Ow! I’ve burnt myself. How did you do that? I picked up a hot dish.

 

Look! Somebody has spilt milk on the carpet.

Well, it wasn’t me. I didn’t do it. (not “hasn’t been…haven’t done”)

I wonder who it was then. (not “who it has been”)

Somebody has spilt milk on the carpet. I wonder who it was then. - English Grammar - Present Perfect and Past - Part 1
Somebody has spilt milk on the carpet. I wonder who it was then.