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