FORM :
1- afirmattive :
was talking were
2- interrogative :
was he talking ? were you
3- negative :
I wasn't , weren't talking
USE :
we use the past progressive :
1- Form action that was in progress and a specefic point of time in the past
2- For a past action that was in progress when it was interrupted by another action
3- For actions that were happening at the same time in the past