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.