I must smile you must smile she must smile we must smile you must smile they must smile
V-ing form
I must be smiling you must be smiling she must be smiling we must be smiling you must be smiling they must be smiling
Perfect
I must have smiled you must have smiled she must have smiled we must have smiled you must have smiled they must have smiled
V-ing perfect
I must have been smiling you must have been smiling she must have been smiling we must have been smiling you must have been smiling they must have been smiling
Negation
Simple form
I must not smile you must not smile she must not smile we must not smile you must not smile they must not smile
V-ing form
I must not be smiling you must not be smiling she must not be smiling we must not be smiling you must not be smiling they must not be smiling
Perfect
I must not have smiled you must not have smiled she must not have smiled we must not have smiled you must not have smiled they must not have smiled
V-ing perfect
I must not have been smiling you must not have been smiling she must not have been smiling we must not have been smiling you must not have been smiling they must not have been smiling
Interrogative form
Simple form
must I smile? must you smile? must she smile? must we smile? must you smile? must they smile?
V-ing form
must I be smiling? must you be smiling? must she be smiling? must we be smiling? must you be smiling? must they be smiling?
Perfect
must I have smiled? must you have smiled? must she have smiled? must we have smiled? must you have smiled? must they have smiled?
V-ing perfect
must I have been smiling? must you have been smiling? must she have been smiling? must we have been smiling? must you have been smiling? must they have been smiling?
Interro-negative form
Simple form
must I not smile? must you not smile? must she not smile? must we not smile? must you not smile? must they not smile?
V-ing form
must I not be smiling? must you not be smiling? must she not be smiling? must we not be smiling? must you not be smiling? must they not be smiling?
Perfect
must I not have smiled? must you not have smiled? must she not have smiled? must we not have smiled? must you not have smiled? must they not have smiled?
V-ing perfect
must I not have been smiling? must you not have been smiling? must she not have been smiling? must we not have been smiling? must you not have been smiling? must they not have been smiling?