"Stava venendo dall'albergo."
Translation:He was coming from the hotel.
as far as I understand: "veniva dall'albergo" also means he was coming from the hotel, what is the difference between these two?
I think the former sentence is used more for things happening in the past, and things happening on an ongoing basis (ex/ she was coming from the hotel [every day]). The gerund is more for current events (ex/ i just spoke with her, she was coming from the hotel). Take this with a grain of salt though.
Why is it wrong when I translate stava into 'he was' instead of 'it was' (first correction given by Duo Lingo) or 'she was', another option that Duo Lingo gives here?
this italian sentence has no explicit subject. It could be a "he", or "she" and a neuter subject too. For instance, a burning smell could come from the hotel (Un odore di bruciato stava venendo dall'albergo). So DL should accept "he", "she" and "it" as well.