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