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