I must hum you must hum she must hum we must hum you must hum they must hum
V-ing form
I must be huming you must be huming she must be huming we must be huming you must be huming they must be huming
Perfect
I must have humed you must have humed she must have humed we must have humed you must have humed they must have humed
V-ing perfect
I must have been huming you must have been huming she must have been huming we must have been huming you must have been huming they must have been huming
Negation
Simple form
I must not hum you must not hum she must not hum we must not hum you must not hum they must not hum
V-ing form
I must not be huming you must not be huming she must not be huming we must not be huming you must not be huming they must not be huming
Perfect
I must not have humed you must not have humed she must not have humed we must not have humed you must not have humed they must not have humed
V-ing perfect
I must not have been huming you must not have been huming she must not have been huming we must not have been huming you must not have been huming they must not have been huming
Interrogative form
Simple form
must I hum? must you hum? must she hum? must we hum? must you hum? must they hum?
V-ing form
must I be huming? must you be huming? must she be huming? must we be huming? must you be huming? must they be huming?
Perfect
must I have humed? must you have humed? must she have humed? must we have humed? must you have humed? must they have humed?
V-ing perfect
must I have been huming? must you have been huming? must she have been huming? must we have been huming? must you have been huming? must they have been huming?
Interro-negative form
Simple form
must I not hum? must you not hum? must she not hum? must we not hum? must you not hum? must they not hum?
V-ing form
must I not be huming? must you not be huming? must she not be huming? must we not be huming? must you not be huming? must they not be huming?
Perfect
must I not have humed? must you not have humed? must she not have humed? must we not have humed? must you not have humed? must they not have humed?
V-ing perfect
must I not have been huming? must you not have been huming? must she not have been huming? must we not have been huming? must you not have been huming? must they not have been huming?