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