El past progressive se forma con el verb. to be en pasado + el otro verbo en ing.
I wasn´t riding my bike.
You Weren´t walking around the park.
She wasn´t using her pen.
They weren´t running during the match.
I was sleeping when you arrived.
Si quieres mas informacion metete aqui:
http://grammar.ccc.commnet.edu/grammar/tenses/past_progressive.htm
