estaban revendiendo
-they/you were reselling
Imperfecto progresivo para el sujeto ellos/ellas/ustedes del verbo revender.

revender

Esta última se había convertido en un problema porque muchos de los que tenían una licencia de costura estaban revendiendo ropa traída del extranjero.
The last had become a problem because many who held a license for dressmaking or tailoring were actually reselling clothes that had been brought in from abroad.
Detuvieron a las personas que estaban revendiendo boletos afuera del estadio.
The people who were scalping tickets outside the stadium were arrested.
Palabra del día
el patinaje