"My sisters were running by your house."
Translation:Mis hermanas estuvieron corriendo por tu casa.
I believe that in Spanish, 'corrían' would be used here, and is used a lot more commonly. The imperfect can translate to "was/were running", "used to run", or "was running"..."estaban corriendo" is only for things that were currently happening in a situation, so it is difficult to interpret it in such a vague sentence like this. However, if my Honors Spanish II knowledge is correct, corrían is used much more commonly and should be accepted as well/in place of estuvieron corriendo