English verb conjugation
COULD KNOW

Irregular verb: know - knew - known

Affirmation

Simple form	V-ing form
I could know you could know he could know we could know you could know they could know	I could be knowing you could be knowing he could be knowing we could be knowing you could be knowing they could be knowing
Perfect	V-ing perfect
I could have known you could have known he could have known we could have known you could have known they could have known	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

Negation

Simple form	V-ing form
I could not know you could not know he could not know we could not know you could not know they could not know	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
Perfect	V-ing perfect
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	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

Interrogative form

Simple form	V-ing form
could I know? could you know? could he know? could we know? could you know? could they know?	could I be knowing? could you be knowing? could he be knowing? could we be knowing? could you be knowing? could they be knowing?
Perfect	V-ing perfect
could I have known? could you have known? could he have known? could we have known? could you have known? could they have known?	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?

Interro-negative form

Simple form	V-ing form
could I not know? could you not know? could he not know? could we not know? could you not know? could they not know?	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?
Perfect	V-ing perfect
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?	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?