you don't know it
Si tú, el papá, no lo sabes, ¿cómo voy a saberlo?
If you, his dad, don’t know, how am I supposed to know?
— Cidade dos Homens (2007)
Si no lo sabes, no sé qué podemos hacer.
If you don't know, I don't know what we can do.
— Escondido (2005)
You really don't know?
Si no lo sabes difícilmente conocerás a hombres.
If you don't know this, you'll hardly meet men.
— Yo vi al diablo (2010)