I can bum you can bum he can bum we can bum you can bum they can bum
V-ing form
I can be bumming you can be bumming he can be bumming we can be bumming you can be bumming they can be bumming
Perfect
I can have bummed you can have bummed he can have bummed we can have bummed you can have bummed they can have bummed
V-ing perfect
I can have been bumming you can have been bumming he can have been bumming we can have been bumming you can have been bumming they can have been bumming
Negation
Simple form
I cannot bum you cannot bum he cannot bum we cannot bum you cannot bum they cannot bum
V-ing form
I cannot be bumming you cannot be bumming he cannot be bumming we cannot be bumming you cannot be bumming they cannot be bumming
Perfect
I cannot have bummed you cannot have bummed he cannot have bummed we cannot have bummed you cannot have bummed they cannot have bummed
V-ing perfect
I cannot have been bumming you cannot have been bumming he cannot have been bumming we cannot have been bumming you cannot have been bumming they cannot have been bumming
Interrogative form
Simple form
can I bum? can you bum? can he bum? can we bum? can you bum? can they bum?
V-ing form
can I be bumming? can you be bumming? can he be bumming? can we be bumming? can you be bumming? can they be bumming?
Perfect
can I have bummed? can you have bummed? can he have bummed? can we have bummed? can you have bummed? can they have bummed?
V-ing perfect
can I have been bumming? can you have been bumming? can he have been bumming? can we have been bumming? can you have been bumming? can they have been bumming?
Interro-negative form
Simple form
can I not bum? can you not bum? can he not bum? can we not bum? can you not bum? can they not bum?
V-ing form
can I not be bumming? can you not be bumming? can he not be bumming? can we not be bumming? can you not be bumming? can they not be bumming?
Perfect
can I not have bummed? can you not have bummed? can he not have bummed? can we not have bummed? can you not have bummed? can they not have bummed?
V-ing perfect
can I not have been bumming? can you not have been bumming? can he not have been bumming? can we not have been bumming? can you not have been bumming? can they not have been bumming?