He has been an architect()he graduated from the university.A.after B.since C.before D.when

He has been an architect()he graduated from the university.
A.after B.since C.before D.when

选B.如果选A的话主句就不该用完成时而该用一般过去时了.

afafgea

额，看错了，是选B。

B.since
因为前边用了完成时