if I had known
I should have known.
I should have known.
Nobody could have known.
Tom debería haberlo sabido.
Tom should have known.
Tienen que haberlo sabido desde el principio.
They must have known from the beginning.
De haberlo sabido no te habría atrapado la mano con la puerta.
Had I known, I wouldn't have caught your hand in the door.
— American Gangster (2007)
I should have known.