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