"We were not sleeping on Friday."
Translation:No estuvimos durmiendo el viernes.
criscarmi, "dormíamos los viernes" doesn't mean "we never sleep on fridays" (if you're triying to say that you rather should say "nosotros nunca dormimos los viernes" which is sad). And to answer skreutzfeldt, saying "no dormíamos el viernes" means almost the same as "no estuvimos durmiendo el viernes" but this unit is about gerunds and the sentence "we were not seleeping..." translates "nosotros no estuvimos durmiendo..."
Ok, now I am seriously confused about the distinction between past preterite and past imperfect. Duo tells me that both estuvimos AND estábamos are correct translations. How can this be? I thought past imperfect was used for past habitual actions, but this sentence, "We were not sleeping on Friday.", indicates an action only taking place once, right?