

Defender o país é o dever de um soldado.
Cumpri o meu dever até ao fim.
Os militares têm direitos e deveres.
"o dever" is in the lesson "Military" (Level 31), along with 13 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.