Perfect Versus Perfect Continuous
I was studying English when you called yesterday.
past continuous
present perfect continuous
Will vary
I love Miami, so I (stay) here for an extended period of time. When I go back home, I (be) here for more than three months.
will stay/am going to stay, will have been
I had been studying English for five years before I moved to the U.S.
past perfect continuous
future continuous
Will vary
I will be studying English when you arrive tonight.
future continuous
future perfect continuous
Will vary
I will have been studying English for over two hours by the time you arrive.
future perfect continuous
past perfect continuous
Will vary