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