Grammar: Present perfect simple (Affirmative & Negative).

Form: have/has + past participle

We use the present perfect for:

• actions which started in the past and continue to the present. They have been here since 2008.
• life experiences (time isn't started) I've tried Chinese food.
• actions that happened in the past and we can see their results in the present. She's broken her leg (When? We don't know, but we can see that her leg is in a cast.)

Note: When we use never in the negative we use have/has.

I have never eaten papaya. (NOT: I haven't never eaten papaya.)

Compare: He has gone to Madrid (He's still there).

                 He has been to Madrid (He's back now).