I could know you could know he could know we could know you could know they could know
Forma con 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
Perfecto
I could have known you could have known he could have known we could have known you could have known they could have known
Perfecto con 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
Negación
Forma simple
I couldn't know you couldn't know he couldn't know we couldn't know you couldn't know they couldn't know
Forma con V-ing
I couldn't be knowing you couldn't be knowing he couldn't be knowing we couldn't be knowing you couldn't be knowing they couldn't be knowing
Perfecto
I couldn't have known you couldn't have known he couldn't have known we couldn't have known you couldn't have known they couldn't have known
Perfecto con V-ing
I couldn't have been knowing you couldn't have been knowing he couldn't have been knowing we couldn't have been knowing you couldn't have been knowing they couldn't 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 con 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?
Perfecto
could I have known? could you have known? could he have known? could we have known? could you have known? could they have known?
Perfecto con 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-negativa
Forma simple
couldn't I know? couldn't you know? couldn't he know? couldn't we know? couldn't you know? couldn't they know?
Forma con V-ing
couldn't I be knowing? couldn't you be knowing? couldn't he be knowing? couldn't we be knowing? couldn't you be knowing? couldn't they be knowing?
Perfecto
couldn't I have known? couldn't you have known? couldn't he have known? couldn't we have known? couldn't you have known? couldn't they have known?
Perfecto con V-ing
couldn't I have been knowing? couldn't you have been knowing? couldn't he have been knowing? couldn't we have been knowing? couldn't you have been knowing? couldn't they have been knowing?