I can barber you can barber he can barber we can barber you can barber they can barber
V-ing form
I can be barbering you can be barbering he can be barbering we can be barbering you can be barbering they can be barbering
Perfect
I can have barbered you can have barbered he can have barbered we can have barbered you can have barbered they can have barbered
V-ing perfect
I can have been barbering you can have been barbering he can have been barbering we can have been barbering you can have been barbering they can have been barbering
Negation
Simple form
I cannot barber you cannot barber he cannot barber we cannot barber you cannot barber they cannot barber
V-ing form
I cannot be barbering you cannot be barbering he cannot be barbering we cannot be barbering you cannot be barbering they cannot be barbering
Perfect
I cannot have barbered you cannot have barbered he cannot have barbered we cannot have barbered you cannot have barbered they cannot have barbered
V-ing perfect
I cannot have been barbering you cannot have been barbering he cannot have been barbering we cannot have been barbering you cannot have been barbering they cannot have been barbering
Interrogative form
Simple form
can I barber? can you barber? can he barber? can we barber? can you barber? can they barber?
V-ing form
can I be barbering? can you be barbering? can he be barbering? can we be barbering? can you be barbering? can they be barbering?
Perfect
can I have barbered? can you have barbered? can he have barbered? can we have barbered? can you have barbered? can they have barbered?
V-ing perfect
can I have been barbering? can you have been barbering? can he have been barbering? can we have been barbering? can you have been barbering? can they have been barbering?
Interro-negative form
Simple form
can I not barber? can you not barber? can he not barber? can we not barber? can you not barber? can they not barber?
V-ing form
can I not be barbering? can you not be barbering? can he not be barbering? can we not be barbering? can you not be barbering? can they not be barbering?
Perfect
can I not have barbered? can you not have barbered? can he not have barbered? can we not have barbered? can you not have barbered? can they not have barbered?
V-ing perfect
can I not have been barbering? can you not have been barbering? can he not have been barbering? can we not have been barbering? can you not have been barbering? can they not have been barbering?