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 could not gridiron you could not gridiron she could not gridiron we could not gridiron you could not gridiron they could not gridiron
V-ing form
I could not be gridironing you could not be gridironing she could not be gridironing we could not be gridironing you could not be gridironing they could not be gridironing
Perfect
I could not have gridironed you could not have gridironed she could not have gridironed we could not have gridironed you could not have gridironed they could not have gridironed
V-ing perfect
I could not have been gridironing you could not have been gridironing she could not have been gridironing we could not have been gridironing you could not have been gridironing they could not 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
could I not gridiron? could you not gridiron? could she not gridiron? could we not gridiron? could you not gridiron? could they not gridiron?
V-ing form
could I not be gridironing? could you not be gridironing? could she not be gridironing? could we not be gridironing? could you not be gridironing? could they not be gridironing?
Perfect
could I not have gridironed? could you not have gridironed? could she not have gridironed? could we not have gridironed? could you not have gridironed? could they not have gridironed?
V-ing perfect
could I not have been gridironing? could you not have been gridironing? could she not have been gridironing? could we not have been gridironing? could you not have been gridironing? could they not have been gridironing?