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