I have posted a pair of examples for contrast:
I guess that it is no use defining them as unknown time. No matter its calling, Ex2 is regarded by all as a continuity, contrary to Ex1, and yet they are both in Present Perfect, unfortunately.Why do we sometimes treat Present Perfect differently, because of the different members of the Past Family?
Ex1: He has lived in Japan in the past. (a finish)
Ex2: he has lived in Japan in the past five years. (a continuity)
:wink: