I could cancel you could cancel he could cancel we could cancel you could cancel they could cancel
V-ing form
I could be cancelling you could be cancelling he could be cancelling we could be cancelling you could be cancelling they could be cancelling
Perfect
I could have cancelled you could have cancelled he could have cancelled we could have cancelled you could have cancelled they could have cancelled
V-ing perfect
I could have been cancelling you could have been cancelling he could have been cancelling we could have been cancelling you could have been cancelling they could have been cancelling
Negation
Simple form
I could not cancel you could not cancel he could not cancel we could not cancel you could not cancel they could not cancel
V-ing form
I could not be cancelling you could not be cancelling he could not be cancelling we could not be cancelling you could not be cancelling they could not be cancelling
Perfect
I could not have cancelled you could not have cancelled he could not have cancelled we could not have cancelled you could not have cancelled they could not have cancelled
V-ing perfect
I could not have been cancelling you could not have been cancelling he could not have been cancelling we could not have been cancelling you could not have been cancelling they could not have been cancelling
Interrogative form
Simple form
could I cancel? could you cancel? could he cancel? could we cancel? could you cancel? could they cancel?
V-ing form
could I be cancelling? could you be cancelling? could he be cancelling? could we be cancelling? could you be cancelling? could they be cancelling?
Perfect
could I have cancelled? could you have cancelled? could he have cancelled? could we have cancelled? could you have cancelled? could they have cancelled?
V-ing perfect
could I have been cancelling? could you have been cancelling? could he have been cancelling? could we have been cancelling? could you have been cancelling? could they have been cancelling?
Interro-negative form
Simple form
could I not cancel? could you not cancel? could he not cancel? could we not cancel? could you not cancel? could they not cancel?
V-ing form
could I not be cancelling? could you not be cancelling? could he not be cancelling? could we not be cancelling? could you not be cancelling? could they not be cancelling?
Perfect
could I not have cancelled? could you not have cancelled? could he not have cancelled? could we not have cancelled? could you not have cancelled? could they not have cancelled?
V-ing perfect
could I not have been cancelling? could you not have been cancelling? could he not have been cancelling? could we not have been cancelling? could you not have been cancelling? could they not have been cancelling?