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