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