I could know you could know he could know we could know you could know they could know
Forma com V-ing
I could be knowing you could be knowing he could be knowing we could be knowing you could be knowing they could be knowing
Perfeito
I could have known you could have known he could have known we could have known you could have known they could have known
Perfeito com V-ing
I could have been knowing you could have been knowing he could have been knowing we could have been knowing you could have been knowing they could have been knowing
Negação
Forma simple
I could not know you could not know he could not know we could not know you could not know they could not know
Forma com V-ing
I could not be knowing you could not be knowing he could not be knowing we could not be knowing you could not be knowing they could not be knowing
Perfeito
I could not have known you could not have known he could not have known we could not have known you could not have known they could not have known
Perfeito com V-ing
I could not have been knowing you could not have been knowing he could not have been knowing we could not have been knowing you could not have been knowing they could not have been knowing
Forma interrogativa
Forma simple
could I know? could you know? could he know? could we know? could you know? could they know?
Forma com V-ing
could I be knowing? could you be knowing? could he be knowing? could we be knowing? could you be knowing? could they be knowing?
Perfeito
could I have known? could you have known? could he have known? could we have known? could you have known? could they have known?
Perfeito com V-ing
could I have been knowing? could you have been knowing? could he have been knowing? could we have been knowing? could you have been knowing? could they have been knowing?
Forma interro-Negação
Forma simple
could I not know? could you not know? could he not know? could we not know? could you not know? could they not know?
Forma com V-ing
could I not be knowing? could you not be knowing? could he not be knowing? could we not be knowing? could you not be knowing? could they not be knowing?
Perfeito
could I not have known? could you not have known? could he not have known? could we not have known? could you not have known? could they not have known?
Perfeito com V-ing
could I not have been knowing? could you not have been knowing? could he not have been knowing? could we not have been knowing? could you not have been knowing? could they not have been knowing?