It was raining all day yesterday.
I was walking in the woods for quite a while.
We were working on our bicycle the other day.

We use the past progressive for two long actions in the past:

While I was doing my homework, my sister was talking on the phone.
Her friend was working in the garden while she was reading a book.
He was fishing while the other boys were looking for worms.

We often use the past progressive and simple when a longer action is interrupted by a shorter one:

I was walking across the field when I saw a plane.
The train was waiting when we arrived at the station.
The phone rang while Gary was making lunch.