Hi,
I found this sentence (with translation) on the “art and performance” section
“A banda estava a fazer uma atuação espetacular ontem”
(The band was giving a spectacular performance yesterday)
Could you please explain why we use the past progressive (estava + infinitive) and not the Preterito perfeito here? It sounds like a “simple” action that terminated.
Olá, @ykv253. The simple past would be perfectly fine here (A banda fez uma atuação espetacular ontem). The past progressive can also be a suitable choice when you want to narrate almost from the perspective that you had while the action was ongoing, as if you were mentally going back in time and revisiting your experience as it happened and not after it ended 
In any case, without any additional context, I agree that the simple past is a more obvious choice.