I could cone you could cone he could cone we could cone you could cone they could cone
V-ing form
I could be coning you could be coning he could be coning we could be coning you could be coning they could be coning
Perfect
I could have coned you could have coned he could have coned we could have coned you could have coned they could have coned
V-ing perfect
I could have been coning you could have been coning he could have been coning we could have been coning you could have been coning they could have been coning
Negation
Simple form
I could not cone you could not cone he could not cone we could not cone you could not cone they could not cone
V-ing form
I could not be coning you could not be coning he could not be coning we could not be coning you could not be coning they could not be coning
Perfect
I could not have coned you could not have coned he could not have coned we could not have coned you could not have coned they could not have coned
V-ing perfect
I could not have been coning you could not have been coning he could not have been coning we could not have been coning you could not have been coning they could not have been coning
Interrogative form
Simple form
could I cone? could you cone? could he cone? could we cone? could you cone? could they cone?
V-ing form
could I be coning? could you be coning? could he be coning? could we be coning? could you be coning? could they be coning?
Perfect
could I have coned? could you have coned? could he have coned? could we have coned? could you have coned? could they have coned?
V-ing perfect
could I have been coning? could you have been coning? could he have been coning? could we have been coning? could you have been coning? could they have been coning?
Interro-negative form
Simple form
could I not cone? could you not cone? could he not cone? could we not cone? could you not cone? could they not cone?
V-ing form
could I not be coning? could you not be coning? could he not be coning? could we not be coning? could you not be coning? could they not be coning?
Perfect
could I not have coned? could you not have coned? could he not have coned? could we not have coned? could you not have coned? could they not have coned?
V-ing perfect
could I not have been coning? could you not have been coning? could he not have been coning? could we not have been coning? could you not have been coning? could they not have been coning?