Examples: use of Present Perfect Simple
Puts emphasis on the result:
Example: She has written five letters.
Action that is still going on:
Example: School has not started yet.
Action that stopped recently:
Example: She has cooked dinner.
Finished action that has an influence on the present:
Example: I have lost my key.
Action that has taken place once, never or several times before the moment of speaking:
Example: I have never been to Australia.