keep quiet
Tom sabe cómo mantener la boca cerrada.
Tom knows how to keep his mouth shut.
A veces, sí sé mantener la boca cerrada.
Sometimes, I do know how to keep my mouth shut.
— Psicosis (1960)
Usted debería mantener la boca cerrada.
You should keep your mouth closed.
Pero no podía mantener la boca cerrada.
But she couldn't keep her mouth shut.
— El prisionero de las montañas (1996)
Tú tienes que aprender a mantener la boca cerrada.
You have to learn to keep your mouth shut.