I can bar you can bar he can bar we can bar you can bar they can bar
V-ing form
I can be barring you can be barring he can be barring we can be barring you can be barring they can be barring
Perfect
I can have barred you can have barred he can have barred we can have barred you can have barred they can have barred
V-ing perfect
I can have been barring you can have been barring he can have been barring we can have been barring you can have been barring they can have been barring
Negation
Simple form
I can't bar you can't bar he can't bar we can't bar you can't bar they can't bar
V-ing form
I can't be barring you can't be barring he can't be barring we can't be barring you can't be barring they can't be barring
Perfect
I can't have barred you can't have barred he can't have barred we can't have barred you can't have barred they can't have barred
V-ing perfect
I can't have been barring you can't have been barring he can't have been barring we can't have been barring you can't have been barring they can't have been barring
Interrogative form
Simple form
can I bar? can you bar? can he bar? can we bar? can you bar? can they bar?
V-ing form
can I be barring? can you be barring? can he be barring? can we be barring? can you be barring? can they be barring?
Perfect
can I have barred? can you have barred? can he have barred? can we have barred? can you have barred? can they have barred?
V-ing perfect
can I have been barring? can you have been barring? can he have been barring? can we have been barring? can you have been barring? can they have been barring?
Interro-negative form
Simple form
can't I bar? can't you bar? can't he bar? can't we bar? can't you bar? can't they bar?
V-ing form
can't I be barring? can't you be barring? can't he be barring? can't we be barring? can't you be barring? can't they be barring?
Perfect
can't I have barred? can't you have barred? can't he have barred? can't we have barred? can't you have barred? can't they have barred?
V-ing perfect
can't I have been barring? can't you have been barring? can't he have been barring? can't we have been barring? can't you have been barring? can't they have been barring?