I could snuff you could snuff he could snuff we could snuff you could snuff they could snuff
V-ing form
I could be snuffing you could be snuffing he could be snuffing we could be snuffing you could be snuffing they could be snuffing
Perfect
I could have snuffed you could have snuffed he could have snuffed we could have snuffed you could have snuffed they could have snuffed
V-ing perfect
I could have been snuffing you could have been snuffing he could have been snuffing we could have been snuffing you could have been snuffing they could have been snuffing
Negation
Simple form
I could not snuff you could not snuff he could not snuff we could not snuff you could not snuff they could not snuff
V-ing form
I could not be snuffing you could not be snuffing he could not be snuffing we could not be snuffing you could not be snuffing they could not be snuffing
Perfect
I could not have snuffed you could not have snuffed he could not have snuffed we could not have snuffed you could not have snuffed they could not have snuffed
V-ing perfect
I could not have been snuffing you could not have been snuffing he could not have been snuffing we could not have been snuffing you could not have been snuffing they could not have been snuffing
Interrogative form
Simple form
could I snuff? could you snuff? could he snuff? could we snuff? could you snuff? could they snuff?
V-ing form
could I be snuffing? could you be snuffing? could he be snuffing? could we be snuffing? could you be snuffing? could they be snuffing?
Perfect
could I have snuffed? could you have snuffed? could he have snuffed? could we have snuffed? could you have snuffed? could they have snuffed?
V-ing perfect
could I have been snuffing? could you have been snuffing? could he have been snuffing? could we have been snuffing? could you have been snuffing? could they have been snuffing?
Interro-negative form
Simple form
could I not snuff? could you not snuff? could he not snuff? could we not snuff? could you not snuff? could they not snuff?
V-ing form
could I not be snuffing? could you not be snuffing? could he not be snuffing? could we not be snuffing? could you not be snuffing? could they not be snuffing?
Perfect
could I not have snuffed? could you not have snuffed? could he not have snuffed? could we not have snuffed? could you not have snuffed? could they not have snuffed?
V-ing perfect
could I not have been snuffing? could you not have been snuffing? could he not have been snuffing? could we not have been snuffing? could you not have been snuffing? could they not have been snuffing?