|When you speak about something in the present perfect you say that
it is not finished,
it is not over yet.
|I have lived here since 2001 (and I still do).
She has studied Latin for three years (and she still does).
We have been friends for a long time (and we still are).
|Maybe the action itself is over,
but the time period is not finished yet.
|I have met him twice this week. (still same week)
Today she has invited me to her party. (still same day)
We haven't met him yet. (still true)
The present perfect is about the past (that's when it started)
In many sentences there are clues that tell you:
this week (month, year...), today,