A friend of mine was in Morocco a few years ago. If I want to ask her how big was the period she spent there, which question from the following two should I use?
How long have you been studying in Morocco?
I'd choose this one, because this is the question I was taught we use when we generally asking how long sth lasted.
How long were you studying in Morocco?
The reason for choosing this one is simple: she was there, and is no longer there - past; therefore - past tense.
Do we still use present perfect progressive for asking how long was the period of the action even when the action is finished?
I would use "How long did you study for in Morocco?" but "How long were you studying in Morocco?" is OK.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
Why do we use the word 'for'? Wouldn't the sentence be correct even without it?How long did you study for in Morocco?