I could end you could end he could end we could end you could end they could end
V-ing form
I could be ending you could be ending he could be ending we could be ending you could be ending they could be ending
Perfect
I could have ended you could have ended he could have ended we could have ended you could have ended they could have ended
V-ing perfect
I could have been ending you could have been ending he could have been ending we could have been ending you could have been ending they could have been ending
Negation
Simple form
I could not end you could not end he could not end we could not end you could not end they could not end
V-ing form
I could not be ending you could not be ending he could not be ending we could not be ending you could not be ending they could not be ending
Perfect
I could not have ended you could not have ended he could not have ended we could not have ended you could not have ended they could not have ended
V-ing perfect
I could not have been ending you could not have been ending he could not have been ending we could not have been ending you could not have been ending they could not have been ending
Interrogative form
Simple form
could I end? could you end? could he end? could we end? could you end? could they end?
V-ing form
could I be ending? could you be ending? could he be ending? could we be ending? could you be ending? could they be ending?
Perfect
could I have ended? could you have ended? could he have ended? could we have ended? could you have ended? could they have ended?
V-ing perfect
could I have been ending? could you have been ending? could he have been ending? could we have been ending? could you have been ending? could they have been ending?
Interro-negative form
Simple form
could I not end? could you not end? could he not end? could we not end? could you not end? could they not end?
V-ing form
could I not be ending? could you not be ending? could he not be ending? could we not be ending? could you not be ending? could they not be ending?
Perfect
could I not have ended? could you not have ended? could he not have ended? could we not have ended? could you not have ended? could they not have ended?
V-ing perfect
could I not have been ending? could you not have been ending? could he not have been ending? could we not have been ending? could you not have been ending? could they not have been ending?