Why is the Present Perfect such a problematic tense?

Seminar paper from the year 2003 in the subject Didactics for the subject English - Pedagogy, Literature Studies, grade: Sehr Gut, University of Innsbruck (Anglistik und Amerikanistik), language: English, abstract: It has to be mentioned that this paper mainly deals with the Present Perfect Simple because otherwise this topic would have become too complex. Furthermore, the present perfect is not a...