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 couldn't chatter you couldn't chatter he couldn't chatter we couldn't chatter you couldn't chatter they couldn't chatter
V-ing form
I couldn't be chattering you couldn't be chattering he couldn't be chattering we couldn't be chattering you couldn't be chattering they couldn't be chattering
Perfect
I couldn't have chattered you couldn't have chattered he couldn't have chattered we couldn't have chattered you couldn't have chattered they couldn't have chattered
V-ing perfect
I couldn't have been chattering you couldn't have been chattering he couldn't have been chattering we couldn't have been chattering you couldn't have been chattering they couldn't 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
couldn't I chatter? couldn't you chatter? couldn't he chatter? couldn't we chatter? couldn't you chatter? couldn't they chatter?
V-ing form
couldn't I be chattering? couldn't you be chattering? couldn't he be chattering? couldn't we be chattering? couldn't you be chattering? couldn't they be chattering?
Perfect
couldn't I have chattered? couldn't you have chattered? couldn't he have chattered? couldn't we have chattered? couldn't you have chattered? couldn't they have chattered?
V-ing perfect
couldn't I have been chattering? couldn't you have been chattering? couldn't he have been chattering? couldn't we have been chattering? couldn't you have been chattering? couldn't they have been chattering?