I could patter you could patter he could patter we could patter you could patter they could patter
V-ing form
I could be pattering you could be pattering he could be pattering we could be pattering you could be pattering they could be pattering
Perfect
I could have pattered you could have pattered he could have pattered we could have pattered you could have pattered they could have pattered
V-ing perfect
I could have been pattering you could have been pattering he could have been pattering we could have been pattering you could have been pattering they could have been pattering
Negation
Simple form
I could not patter you could not patter he could not patter we could not patter you could not patter they could not patter
V-ing form
I could not be pattering you could not be pattering he could not be pattering we could not be pattering you could not be pattering they could not be pattering
Perfect
I could not have pattered you could not have pattered he could not have pattered we could not have pattered you could not have pattered they could not have pattered
V-ing perfect
I could not have been pattering you could not have been pattering he could not have been pattering we could not have been pattering you could not have been pattering they could not have been pattering
Interrogative form
Simple form
could I patter? could you patter? could he patter? could we patter? could you patter? could they patter?
V-ing form
could I be pattering? could you be pattering? could he be pattering? could we be pattering? could you be pattering? could they be pattering?
Perfect
could I have pattered? could you have pattered? could he have pattered? could we have pattered? could you have pattered? could they have pattered?
V-ing perfect
could I have been pattering? could you have been pattering? could he have been pattering? could we have been pattering? could you have been pattering? could they have been pattering?
Interro-negative form
Simple form
could I not patter? could you not patter? could he not patter? could we not patter? could you not patter? could they not patter?
V-ing form
could I not be pattering? could you not be pattering? could he not be pattering? could we not be pattering? could you not be pattering? could they not be pattering?
Perfect
could I not have pattered? could you not have pattered? could he not have pattered? could we not have pattered? could you not have pattered? could they not have pattered?
V-ing perfect
could I not have been pattering? could you not have been pattering? could he not have been pattering? could we not have been pattering? could you not have been pattering? could they not have been pattering?