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