Bonjour
FOR ou SINCE.
FOR > pour exprimer la durée d'une action
SINCE > pour exprimer quand l'action a commencé, le point de départ ...
a- I haven't seen you for ages.
b- He has been studying since 2012.
c- He has been asleep for ten hours!
d- They've stayed here for a while now.
e- He has been working there ever since he graduated.
-
Bonne soirée