I could snap you could snap she could snap we could snap you could snap they could snap
V-ing form
I could be snapping you could be snapping she could be snapping we could be snapping you could be snapping they could be snapping
Perfect
I could have snapped you could have snapped she 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 she 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 she 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 she 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 she 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 she 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 she snap? could we snap? could you snap? could they snap?
V-ing form
could I be snapping? could you be snapping? could she be snapping? could we be snapping? could you be snapping? could they be snapping?
Perfect
could I have snapped? could you have snapped? could she 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 she 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 she 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 she 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 she 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 she have been snapping? couldn't we have been snapping? couldn't you have been snapping? couldn't they have been snapping?