Как ответить? what were you doing yesterday morning? what were you doing at 4 o'clock in the afternoon yesterday? what were you doing at 9 o'clock last night? what were you doing when our teacher came in?

I was having breakfast yesterday morning.
I was doing my homework at 4 o’clock in the afternoon yesterday.
I was watching a movie at 9 o’clock last night.
I was cleaning the board when the teacher came in.