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