Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could supper you could supper she could supper we could supper you could supper they could supper
V-ing form
I could be suppering you could be suppering she could be suppering we could be suppering you could be suppering they could be suppering
Perfect
I could have suppered you could have suppered she could have suppered we could have suppered you could have suppered they could have suppered
V-ing perfect
I could have been suppering you could have been suppering she could have been suppering we could have been suppering you could have been suppering they could have been suppering
Negation
Simple form
I couldn't supper you couldn't supper she couldn't supper we couldn't supper you couldn't supper they couldn't supper
V-ing form
I couldn't be suppering you couldn't be suppering she couldn't be suppering we couldn't be suppering you couldn't be suppering they couldn't be suppering
Perfect
I couldn't have suppered you couldn't have suppered she couldn't have suppered we couldn't have suppered you couldn't have suppered they couldn't have suppered
V-ing perfect
I couldn't have been suppering you couldn't have been suppering she couldn't have been suppering we couldn't have been suppering you couldn't have been suppering they couldn't have been suppering
Interrogative form
Simple form
could I supper? could you supper? could she supper? could we supper? could you supper? could they supper?
V-ing form
could I be suppering? could you be suppering? could she be suppering? could we be suppering? could you be suppering? could they be suppering?
Perfect
could I have suppered? could you have suppered? could she have suppered? could we have suppered? could you have suppered? could they have suppered?
V-ing perfect
could I have been suppering? could you have been suppering? could she have been suppering? could we have been suppering? could you have been suppering? could they have been suppering?
Interro-negative form
Simple form
couldn't I supper? couldn't you supper? couldn't she supper? couldn't we supper? couldn't you supper? couldn't they supper?
V-ing form
couldn't I be suppering? couldn't you be suppering? couldn't she be suppering? couldn't we be suppering? couldn't you be suppering? couldn't they be suppering?
Perfect
couldn't I have suppered? couldn't you have suppered? couldn't she have suppered? couldn't we have suppered? couldn't you have suppered? couldn't they have suppered?
V-ing perfect
couldn't I have been suppering? couldn't you have been suppering? couldn't she have been suppering? couldn't we have been suppering? couldn't you have been suppering? couldn't they have been suppering?