Breakdown of Su plan era comprar los zapatos para la reventa cuando abrieran las puertas.
ser
to be
comprar
to buy
el zapato
the shoe
la puerta
the door
Questions & Answers about Su plan era comprar los zapatos para la reventa cuando abrieran las puertas.
Why do we use the imperfect subjunctive (abrieran) after cuando here?
We use it to show an anticipated action in the past. If this plan were happening today, we would use the present subjunctive for a future event that hasn't happened yet (cuando abran las puertas). Because this sentence is set in the past (Su plan era...), we have to "backshift" our tenses. The doors opening was a future event from the perspective of that past moment, so the subjunctive shifts back to the imperfect form (abrieran).
In the phrase cuando abrieran las puertas, are the doors the subject doing the opening?
No, las puertas is the direct object here, and the implied subject is "they" (the store employees or organizers). If the sentence meant "when the doors opened (themselves)," it would normally use the reflexive form to show that the doors are the subject: cuando se abrieran las puertas.
Why is it para la reventa and not por la reventa?
Could I say cuando abriesen las puertas instead?