Past Continuous

Use: actions happening in the past when something else happened or was happening.

Form: past BE verb (was, were) + VERB-ing
She was baking a pie when I left this morning.
She was writing the letter while watching the game. (was happening at the same time)
They were driving to the game when the accident happened. (was happening before)

Negative Form: was/were not VERB-ing
I was not wearing pajamas when the police came. I was wearing comfortable clothes.