1-non
2-la durée
3-devenu has been qui combien le present de l'auxiliaire HAVE et le participe passe de BE
4-une situation/ activite en cours
5- for two months
6- si on parle de durée on emploie FOR
si on indique le moment precis on emploie SINCE
7-FOR three days
SINCE monday
FOR two hours
SINCE three o'clock
SINCE the war
SINCE 2008
8-a-he is reading
b-he has been reading for five minutes
c-she is sleeping
d-she has been sleeping since breakfast
