why doesn't os edificios são muito grandes work?
muito grandes = very big. huge = enorme. Duo prefers more literal translations....
Is there a difference between edifício and prédio?
They mean the same. Prédio is usually used in conversation and Edifício is what you see on the front of a building along with its name ;)
I used "imenso" instead of "enorme". It should be considered, because both two words have the same meaning in Brazil