I could chat you could chat he could chat we could chat you could chat they could chat
V-ing form
I could be chatting you could be chatting he could be chatting we could be chatting you could be chatting they could be chatting
Perfect
I could have chatted you could have chatted he could have chatted we could have chatted you could have chatted they could have chatted
V-ing perfect
I could have been chatting you could have been chatting he could have been chatting we could have been chatting you could have been chatting they could have been chatting
Negation
Simple form
I couldn't chat you couldn't chat he couldn't chat we couldn't chat you couldn't chat they couldn't chat
V-ing form
I couldn't be chatting you couldn't be chatting he couldn't be chatting we couldn't be chatting you couldn't be chatting they couldn't be chatting
Perfect
I couldn't have chatted you couldn't have chatted he couldn't have chatted we couldn't have chatted you couldn't have chatted they couldn't have chatted
V-ing perfect
I couldn't have been chatting you couldn't have been chatting he couldn't have been chatting we couldn't have been chatting you couldn't have been chatting they couldn't have been chatting
Interrogative form
Simple form
could I chat? could you chat? could he chat? could we chat? could you chat? could they chat?
V-ing form
could I be chatting? could you be chatting? could he be chatting? could we be chatting? could you be chatting? could they be chatting?
Perfect
could I have chatted? could you have chatted? could he have chatted? could we have chatted? could you have chatted? could they have chatted?
V-ing perfect
could I have been chatting? could you have been chatting? could he have been chatting? could we have been chatting? could you have been chatting? could they have been chatting?
Interro-negative form
Simple form
couldn't I chat? couldn't you chat? couldn't he chat? couldn't we chat? couldn't you chat? couldn't they chat?
V-ing form
couldn't I be chatting? couldn't you be chatting? couldn't he be chatting? couldn't we be chatting? couldn't you be chatting? couldn't they be chatting?
Perfect
couldn't I have chatted? couldn't you have chatted? couldn't he have chatted? couldn't we have chatted? couldn't you have chatted? couldn't they have chatted?
V-ing perfect
couldn't I have been chatting? couldn't you have been chatting? couldn't he have been chatting? couldn't we have been chatting? couldn't you have been chatting? couldn't they have been chatting?