Past Continuous Uses

—Actions in the past that take place at a particular time

Eg:What were you doing last evening at 8:45?
I was watching TV

—With the Past Simple to refer to a long action that is interrupted by a shorter one.("When"or "While" are the habitual conjunctions)

Eg:We were talking about our last holidays when the boss came into the office and got angry

—Two actions developing at the same time in the past ("While" is the habitual conjunction)

Eg:While my boss was talking to me, I was dreaming of my last holidays in Cancún