

Naquela noite sem lua, o firmamento estava salpicado de estrelas.
Os antigos navegadores orientavam-se pelos astros do firmamento.
Deitados na areia, contemplávamos o firmamento em silêncio absoluto.
"o firmamento" is in the lesson "Nature" (Level 21), along with 11 other useful words. LinDuo has 180 topic lessons like this one, 2,380 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.