"The winds blow through the house."
Translation:Venti per villam perflant.
Why is it "venti per villam perflat" but "venti silvam perflat"? Sometimes you need the other per and sometimes not, but the translation remains the same "blow through"
Per is optional. The verb perflare tends not to take the preposition per in extant literature from what I can tell but I have not checked TLL. Some verbs with prefix such as advenire sometimes were accompanied by ad, doubling up on the preposition. Venti domum perflant should work here or Venti villam perflant. Currently (Nov 3, 2020) the former is rejected. Villa was a country house. Elites such as Cicero owned several (through marriage to the wealthy Terentia). Here's a discussion of their country home at Arpinum: https://www.gardenvisit.com/history_theory/library_online_ebooks/ml_gothein_history_garden_art_design/cicero_urbane_villa
It probably should be accepted. Most people lived in crowded tenements rather than a city domus or country villa. https://www.khanacademy.org/humanities/ancient-art-civilizations/roman/x7e914f5b:beginner-guides-to-roman-architecture/a/roman-domestic-architecture-domus