I could wax you could wax he could wax we could wax you could wax they could wax
V-ing form
I could be waxing you could be waxing he could be waxing we could be waxing you could be waxing they could be waxing
Perfect
I could have waxed you could have waxed he could have waxed we could have waxed you could have waxed they could have waxed
V-ing perfect
I could have been waxing you could have been waxing he could have been waxing we could have been waxing you could have been waxing they could have been waxing
Negation
Simple form
I could not wax you could not wax he could not wax we could not wax you could not wax they could not wax
V-ing form
I could not be waxing you could not be waxing he could not be waxing we could not be waxing you could not be waxing they could not be waxing
Perfect
I could not have waxed you could not have waxed he could not have waxed we could not have waxed you could not have waxed they could not have waxed
V-ing perfect
I could not have been waxing you could not have been waxing he could not have been waxing we could not have been waxing you could not have been waxing they could not have been waxing
Interrogative form
Simple form
could I wax? could you wax? could he wax? could we wax? could you wax? could they wax?
V-ing form
could I be waxing? could you be waxing? could he be waxing? could we be waxing? could you be waxing? could they be waxing?
Perfect
could I have waxed? could you have waxed? could he have waxed? could we have waxed? could you have waxed? could they have waxed?
V-ing perfect
could I have been waxing? could you have been waxing? could he have been waxing? could we have been waxing? could you have been waxing? could they have been waxing?
Interro-negative form
Simple form
could I not wax? could you not wax? could he not wax? could we not wax? could you not wax? could they not wax?
V-ing form
could I not be waxing? could you not be waxing? could he not be waxing? could we not be waxing? could you not be waxing? could they not be waxing?
Perfect
could I not have waxed? could you not have waxed? could he not have waxed? could we not have waxed? could you not have waxed? could they not have waxed?
V-ing perfect
could I not have been waxing? could you not have been waxing? could he not have been waxing? could we not have been waxing? could you not have been waxing? could they not have been waxing?