In Nicholas J. Brown's book, exercise 27/4 has a sentence, roughly expressing the same idea (with and without Past Passive Participles [short,perfective,transitive]) and the question and answer are in the pictures.
My primary question was about the last pair of PPP and past perfective verb, but an additional very related part may ask about mood - I'm not sure it is a good idea to split into two questions...
Clearly, PPPs are passive, and I would say that past tense verbs are active. Here are some from the two situations;
уже проданы / уже продали : 'had already been sold' / 'had already sold' - Is this a passive construction versus an active construction?
В среду было объявлено / В среду объявили : 'On Wednesday it was announced' / 'On Wednesday they announced' - Also seems passive vs active
было написано / написал : '(it) was written' / '(the letter) wrote' - Again, passive vs active voice.
будут куплены / купят : 'would be bought' / '(they) would buy' - Again, passive and then active.
4b. An aside, is this true (maybe this is starting to mix tense and mood...) 'would be bought' = 'will be bought' Actually I would have assumed this conditional English translation come from a Russian sentence with 'бы' in it?
But what happened here? Why the same?
Мы были очень удивлены / Мы очень удивились : 'We were very surprised' -- in both cases
Should the first situation be translated as: 'It was surprising to us...' - too much like impersonal dative case construction?
Maybe 'It very much surprised us'?
PS If necessary I will reword my sentence upon receiving suggestions.