Musí být "You could have known (that) she will would / was going to say no.
Mohla jsi vědět, že to takhle dopadne. You could have known (that) it will would / was going to turn out like this.
Mohl vědět, že řeknu pravdu, He could have known (that) I will would / was going to tell the truth.
Kdo tehdy mohl vědět, že přijde nějaký vir? Who could then have known (that) a virus will would / was going to come?