1. To maintain focus, attention, or vigilance throughout the entire duration of an event, task, or situation until its conclusion
You need to stay attentive until the final whistle of the game.
Você precisa permanecer atento até o final do jogo.
2. To not lose concentration or alertness despite fatigue or distraction as something continues to its end
The students had to remain alert through the entire exam.
Os alunos tiveram que permanecer atentos até o final do exame.