I could gridiron you could gridiron she could gridiron we could gridiron you could gridiron they could gridiron
V-ing form
I could be gridironing you could be gridironing she could be gridironing we could be gridironing you could be gridironing they could be gridironing
Perfect
I could have gridironed you could have gridironed she 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 she 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 she 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 she 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 she 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 she 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 she gridiron? could we gridiron? could you gridiron? could they gridiron?
V-ing form
could I be gridironing? could you be gridironing? could she be gridironing? could we be gridironing? could you be gridironing? could they be gridironing?
Perfect
could I have gridironed? could you have gridironed? could she 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 she 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 she 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 she 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 she 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 she have been gridironing? couldn't we have been gridironing? couldn't you have been gridironing? couldn't they have been gridironing?