to have known
I wish I had known.
I wish I had known the truth.
Quem me dera ter sabido que isso ia acontecer.
I wish I had known that was going to happen.
Vendo que não está surpreso, acho que você deve ter sabido.
Seeing that you're not surprised, I guess you must have known.
No one could have known.
Tom deveria ter sabido que estaríamos aqui hoje.
Tom should have known that we would be here today.
Eu não poderia ter sabido disso.
I couldn't have known that.