Bonjour
For = durée
since = indique un point de départ
a- I have been playing football since I was 7 years old. (depuis)
b- She has been working as an "au pair" for a year now . (pendant)
c- I have been looking for a work's placement for several weeks.(pendant)
d- He has been assisting the sports coach since the last school break.(depuis)
bonne soirée ☺☺☺