I'm still confused about perfect contitious. Most of sources say that the group of tenses are used to show perfect **duration** of an activity in time or number of times. My question is it exactly for that task? or the tenses can be **real** usful without pointing time or number of times? Yes, i saw some examples without durations, but i can't handle the real usefulness. For example:
I've been watching TV.
Why can't i just say something like this? :
I was watching TV couple of minutes ago