I can chat you can chat he can chat we can chat you can chat they can chat
V-ing form
I can be chatting you can be chatting he can be chatting we can be chatting you can be chatting they can be chatting
Perfect
I can have chatted you can have chatted he can have chatted we can have chatted you can have chatted they can have chatted
V-ing perfect
I can have been chatting you can have been chatting he can have been chatting we can have been chatting you can have been chatting they can have been chatting
Negation
Simple form
I cannot chat you cannot chat he cannot chat we cannot chat you cannot chat they cannot chat
V-ing form
I cannot be chatting you cannot be chatting he cannot be chatting we cannot be chatting you cannot be chatting they cannot be chatting
Perfect
I cannot have chatted you cannot have chatted he cannot have chatted we cannot have chatted you cannot have chatted they cannot have chatted
V-ing perfect
I cannot have been chatting you cannot have been chatting he cannot have been chatting we cannot have been chatting you cannot have been chatting they cannot have been chatting
Interrogative form
Simple form
can I chat? can you chat? can he chat? can we chat? can you chat? can they chat?
V-ing form
can I be chatting? can you be chatting? can he be chatting? can we be chatting? can you be chatting? can they be chatting?
Perfect
can I have chatted? can you have chatted? can he have chatted? can we have chatted? can you have chatted? can they have chatted?
V-ing perfect
can I have been chatting? can you have been chatting? can he have been chatting? can we have been chatting? can you have been chatting? can they have been chatting?
Interro-negative form
Simple form
can I not chat? can you not chat? can he not chat? can we not chat? can you not chat? can they not chat?
V-ing form
can I not be chatting? can you not be chatting? can he not be chatting? can we not be chatting? can you not be chatting? can they not be chatting?
Perfect
can I not have chatted? can you not have chatted? can he not have chatted? can we not have chatted? can you not have chatted? can they not have chatted?
V-ing perfect
can I not have been chatting? can you not have been chatting? can he not have been chatting? can we not have been chatting? can you not have been chatting? can they not have been chatting?