I could chatter you could chatter he could chatter we could chatter you could chatter they could chatter
V-ing form
I could be chattering you could be chattering he could be chattering we could be chattering you could be chattering they could be chattering
Perfect
I could have chattered you could have chattered he could have chattered we could have chattered you could have chattered they could have chattered
V-ing perfect
I could have been chattering you could have been chattering he could have been chattering we could have been chattering you could have been chattering they could have been chattering
Negation
Simple form
I could not chatter you could not chatter he could not chatter we could not chatter you could not chatter they could not chatter
V-ing form
I could not be chattering you could not be chattering he could not be chattering we could not be chattering you could not be chattering they could not be chattering
Perfect
I could not have chattered you could not have chattered he could not have chattered we could not have chattered you could not have chattered they could not have chattered
V-ing perfect
I could not have been chattering you could not have been chattering he could not have been chattering we could not have been chattering you could not have been chattering they could not have been chattering
Interrogative form
Simple form
could I chatter? could you chatter? could he chatter? could we chatter? could you chatter? could they chatter?
V-ing form
could I be chattering? could you be chattering? could he be chattering? could we be chattering? could you be chattering? could they be chattering?
Perfect
could I have chattered? could you have chattered? could he have chattered? could we have chattered? could you have chattered? could they have chattered?
V-ing perfect
could I have been chattering? could you have been chattering? could he have been chattering? could we have been chattering? could you have been chattering? could they have been chattering?
Interro-negative form
Simple form
could I not chatter? could you not chatter? could he not chatter? could we not chatter? could you not chatter? could they not chatter?
V-ing form
could I not be chattering? could you not be chattering? could he not be chattering? could we not be chattering? could you not be chattering? could they not be chattering?
Perfect
could I not have chattered? could you not have chattered? could he not have chattered? could we not have chattered? could you not have chattered? could they not have chattered?
V-ing perfect
could I not have been chattering? could you not have been chattering? could he not have been chattering? could we not have been chattering? could you not have been chattering? could they not have been chattering?