Construction of the past progressive tense :
was + going
were + going
I met my friend when I was walking along High Street.
Was it my car outside when you came in ?
As I was living the house, the phone rang.
When I arrived at the office, the rain stop to falling.
The past progressive tense express an activity which lasted for some time in a definite past period.
This time last year there is no Covid19 pandemic.
He was watching movies all evening.
The boys are playing outside all day.
The past progressive tense may indicate two or more activities continuing at the same time in a definite past period.
David was playing the guitar and we were sang the song.
They were playing PS4 all afternoon yesterday, while I was reading in the next room.
The past progressive tense indicates that an activity was progress at a definite past moment in time.
I was running along the street when the tower clock struck a noon.
At 8.pm we were watching movie at the cinema.
What were you doing last night at 8 o’clock ?