I could tin you could tin she could tin we could tin you could tin they could tin
V-ing form
I could be tinning you could be tinning she could be tinning we could be tinning you could be tinning they could be tinning
Perfect
I could have tinned you could have tinned she could have tinned we could have tinned you could have tinned they could have tinned
V-ing perfect
I could have been tinning you could have been tinning she could have been tinning we could have been tinning you could have been tinning they could have been tinning
Negation
Simple form
I could not tin you could not tin she could not tin we could not tin you could not tin they could not tin
V-ing form
I could not be tinning you could not be tinning she could not be tinning we could not be tinning you could not be tinning they could not be tinning
Perfect
I could not have tinned you could not have tinned she could not have tinned we could not have tinned you could not have tinned they could not have tinned
V-ing perfect
I could not have been tinning you could not have been tinning she could not have been tinning we could not have been tinning you could not have been tinning they could not have been tinning
Interrogative form
Simple form
could I tin? could you tin? could she tin? could we tin? could you tin? could they tin?
V-ing form
could I be tinning? could you be tinning? could she be tinning? could we be tinning? could you be tinning? could they be tinning?
Perfect
could I have tinned? could you have tinned? could she have tinned? could we have tinned? could you have tinned? could they have tinned?
V-ing perfect
could I have been tinning? could you have been tinning? could she have been tinning? could we have been tinning? could you have been tinning? could they have been tinning?
Interro-negative form
Simple form
could I not tin? could you not tin? could she not tin? could we not tin? could you not tin? could they not tin?
V-ing form
could I not be tinning? could you not be tinning? could she not be tinning? could we not be tinning? could you not be tinning? could they not be tinning?
Perfect
could I not have tinned? could you not have tinned? could she not have tinned? could we not have tinned? could you not have tinned? could they not have tinned?
V-ing perfect
could I not have been tinning? could you not have been tinning? could she not have been tinning? could we not have been tinning? could you not have been tinning? could they not have been tinning?