I could snap you could snap he could snap we could snap you could snap they could snap
V-ing form
I could be snapping you could be snapping he could be snapping we could be snapping you could be snapping they could be snapping
Perfect
I could have snapped you could have snapped he could have snapped we could have snapped you could have snapped they could have snapped
V-ing perfect
I could have been snapping you could have been snapping he could have been snapping we could have been snapping you could have been snapping they could have been snapping
Negation
Simple form
I couldn't snap you couldn't snap he couldn't snap we couldn't snap you couldn't snap they couldn't snap
V-ing form
I couldn't be snapping you couldn't be snapping he couldn't be snapping we couldn't be snapping you couldn't be snapping they couldn't be snapping
Perfect
I couldn't have snapped you couldn't have snapped he couldn't have snapped we couldn't have snapped you couldn't have snapped they couldn't have snapped
V-ing perfect
I couldn't have been snapping you couldn't have been snapping he couldn't have been snapping we couldn't have been snapping you couldn't have been snapping they couldn't have been snapping
Interrogative form
Simple form
could I snap? could you snap? could he snap? could we snap? could you snap? could they snap?
V-ing form
could I be snapping? could you be snapping? could he be snapping? could we be snapping? could you be snapping? could they be snapping?
Perfect
could I have snapped? could you have snapped? could he have snapped? could we have snapped? could you have snapped? could they have snapped?
V-ing perfect
could I have been snapping? could you have been snapping? could he have been snapping? could we have been snapping? could you have been snapping? could they have been snapping?
Interro-negative form
Simple form
couldn't I snap? couldn't you snap? couldn't he snap? couldn't we snap? couldn't you snap? couldn't they snap?
V-ing form
couldn't I be snapping? couldn't you be snapping? couldn't he be snapping? couldn't we be snapping? couldn't you be snapping? couldn't they be snapping?
Perfect
couldn't I have snapped? couldn't you have snapped? couldn't he have snapped? couldn't we have snapped? couldn't you have snapped? couldn't they have snapped?
V-ing perfect
couldn't I have been snapping? couldn't you have been snapping? couldn't he have been snapping? couldn't we have been snapping? couldn't you have been snapping? couldn't they have been snapping?