I could supply you could supply he could supply we could supply you could supply they could supply
V-ing form
I could be supplying you could be supplying he could be supplying we could be supplying you could be supplying they could be supplying
Perfect
I could have supplied you could have supplied he could have supplied we could have supplied you could have supplied they could have supplied
V-ing perfect
I could have been supplying you could have been supplying he could have been supplying we could have been supplying you could have been supplying they could have been supplying
Negation
Simple form
I couldn't supply you couldn't supply he couldn't supply we couldn't supply you couldn't supply they couldn't supply
V-ing form
I couldn't be supplying you couldn't be supplying he couldn't be supplying we couldn't be supplying you couldn't be supplying they couldn't be supplying
Perfect
I couldn't have supplied you couldn't have supplied he couldn't have supplied we couldn't have supplied you couldn't have supplied they couldn't have supplied
V-ing perfect
I couldn't have been supplying you couldn't have been supplying he couldn't have been supplying we couldn't have been supplying you couldn't have been supplying they couldn't have been supplying
Interrogative form
Simple form
could I supply? could you supply? could he supply? could we supply? could you supply? could they supply?
V-ing form
could I be supplying? could you be supplying? could he be supplying? could we be supplying? could you be supplying? could they be supplying?
Perfect
could I have supplied? could you have supplied? could he have supplied? could we have supplied? could you have supplied? could they have supplied?
V-ing perfect
could I have been supplying? could you have been supplying? could he have been supplying? could we have been supplying? could you have been supplying? could they have been supplying?
Interro-negative form
Simple form
couldn't I supply? couldn't you supply? couldn't he supply? couldn't we supply? couldn't you supply? couldn't they supply?
V-ing form
couldn't I be supplying? couldn't you be supplying? couldn't he be supplying? couldn't we be supplying? couldn't you be supplying? couldn't they be supplying?
Perfect
couldn't I have supplied? couldn't you have supplied? couldn't he have supplied? couldn't we have supplied? couldn't you have supplied? couldn't they have supplied?
V-ing perfect
couldn't I have been supplying? couldn't you have been supplying? couldn't he have been supplying? couldn't we have been supplying? couldn't you have been supplying? couldn't they have been supplying?