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