didn't know anything
Hasta ayer no sabía nada de eso.
Until yesterday I knew nothing about that.
Tom no sabía nada.
Tom didn't know anything.
El hombre, del cual no sabía nada, me conocía bien.
The man, about whom I knew nothing, knew me well.
Cari, mi amor, pero hacía un montón que no sabía nada de vos.
Cari, my love—it’s been ages since I heard from you.
— Diarios de motocicleta (2004)
Tom no sabía nada acerca de lo que estaba pasando.
Tom had no idea what was going on.
I didn't know anything about him.
Tom fingía que no sabía nada de Mary.
Tom pretended he knew nothing about Mary.