I must snap you must snap she must snap we must snap you must snap they must snap
V-ing form
I must be snapping you must be snapping she must be snapping we must be snapping you must be snapping they must be snapping
Perfect
I must have snapped you must have snapped she must have snapped we must have snapped you must have snapped they must have snapped
V-ing perfect
I must have been snapping you must have been snapping she must have been snapping we must have been snapping you must have been snapping they must have been snapping
Negation
Simple form
I mustn't snap you mustn't snap she mustn't snap we mustn't snap you mustn't snap they mustn't snap
V-ing form
I mustn't be snapping you mustn't be snapping she mustn't be snapping we mustn't be snapping you mustn't be snapping they mustn't be snapping
Perfect
I mustn't have snapped you mustn't have snapped she mustn't have snapped we mustn't have snapped you mustn't have snapped they mustn't have snapped
V-ing perfect
I mustn't have been snapping you mustn't have been snapping she mustn't have been snapping we mustn't have been snapping you mustn't have been snapping they mustn't have been snapping
Interrogative form
Simple form
must I snap? must you snap? must she snap? must we snap? must you snap? must they snap?
V-ing form
must I be snapping? must you be snapping? must she be snapping? must we be snapping? must you be snapping? must they be snapping?
Perfect
must I have snapped? must you have snapped? must she have snapped? must we have snapped? must you have snapped? must they have snapped?
V-ing perfect
must I have been snapping? must you have been snapping? must she have been snapping? must we have been snapping? must you have been snapping? must they have been snapping?
Interro-negative form
Simple form
mustn't I snap? mustn't you snap? mustn't she snap? mustn't we snap? mustn't you snap? mustn't they snap?
V-ing form
mustn't I be snapping? mustn't you be snapping? mustn't she be snapping? mustn't we be snapping? mustn't you be snapping? mustn't they be snapping?
Perfect
mustn't I have snapped? mustn't you have snapped? mustn't she have snapped? mustn't we have snapped? mustn't you have snapped? mustn't they have snapped?
V-ing perfect
mustn't I have been snapping? mustn't you have been snapping? mustn't she have been snapping? mustn't we have been snapping? mustn't you have been snapping? mustn't they have been snapping?