Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could know know you could know know he could know know we could know know you could know know they could know know
V-ing form
I could be know knowing you could be know knowing he could be know knowing we could be know knowing you could be know knowing they could be know knowing
Perfect
I could have know knowed you could have know knowed he could have know knowed we could have know knowed you could have know knowed they could have know knowed
V-ing perfect
I could have been know knowing you could have been know knowing he could have been know knowing we could have been know knowing you could have been know knowing they could have been know knowing
Negation
Simple form
I could not know know you could not know know he could not know know we could not know know you could not know know they could not know know
V-ing form
I could not be know knowing you could not be know knowing he could not be know knowing we could not be know knowing you could not be know knowing they could not be know knowing
Perfect
I could not have know knowed you could not have know knowed he could not have know knowed we could not have know knowed you could not have know knowed they could not have know knowed
V-ing perfect
I could not have been know knowing you could not have been know knowing he could not have been know knowing we could not have been know knowing you could not have been know knowing they could not have been know knowing
Interrogative form
Simple form
could I know know? could you know know? could he know know? could we know know? could you know know? could they know know?
V-ing form
could I be know knowing? could you be know knowing? could he be know knowing? could we be know knowing? could you be know knowing? could they be know knowing?
Perfect
could I have know knowed? could you have know knowed? could he have know knowed? could we have know knowed? could you have know knowed? could they have know knowed?
V-ing perfect
could I have been know knowing? could you have been know knowing? could he have been know knowing? could we have been know knowing? could you have been know knowing? could they have been know knowing?
Interro-negative form
Simple form
could I not know know? could you not know know? could he not know know? could we not know know? could you not know know? could they not know know?
V-ing form
could I not be know knowing? could you not be know knowing? could he not be know knowing? could we not be know knowing? could you not be know knowing? could they not be know knowing?
Perfect
could I not have know knowed? could you not have know knowed? could he not have know knowed? could we not have know knowed? could you not have know knowed? could they not have know knowed?
V-ing perfect
could I not have been know knowing? could you not have been know knowing? could he not have been know knowing? could we not have been know knowing? could you not have been know knowing? could they not have been know knowing?