I must differ you must differ he must differ we must differ you must differ they must differ
V-ing form
I must be differing you must be differing he must be differing we must be differing you must be differing they must be differing
Perfect
I must have differed you must have differed he must have differed we must have differed you must have differed they must have differed
V-ing perfect
I must have been differing you must have been differing he must have been differing we must have been differing you must have been differing they must have been differing
Negation
Simple form
I mustn't differ you mustn't differ he mustn't differ we mustn't differ you mustn't differ they mustn't differ
V-ing form
I mustn't be differing you mustn't be differing he mustn't be differing we mustn't be differing you mustn't be differing they mustn't be differing
Perfect
I mustn't have differed you mustn't have differed he mustn't have differed we mustn't have differed you mustn't have differed they mustn't have differed
V-ing perfect
I mustn't have been differing you mustn't have been differing he mustn't have been differing we mustn't have been differing you mustn't have been differing they mustn't have been differing
Interrogative form
Simple form
must I differ? must you differ? must he differ? must we differ? must you differ? must they differ?
V-ing form
must I be differing? must you be differing? must he be differing? must we be differing? must you be differing? must they be differing?
Perfect
must I have differed? must you have differed? must he have differed? must we have differed? must you have differed? must they have differed?
V-ing perfect
must I have been differing? must you have been differing? must he have been differing? must we have been differing? must you have been differing? must they have been differing?
Interro-negative form
Simple form
mustn't I differ? mustn't you differ? mustn't he differ? mustn't we differ? mustn't you differ? mustn't they differ?
V-ing form
mustn't I be differing? mustn't you be differing? mustn't he be differing? mustn't we be differing? mustn't you be differing? mustn't they be differing?
Perfect
mustn't I have differed? mustn't you have differed? mustn't he have differed? mustn't we have differed? mustn't you have differed? mustn't they have differed?
V-ing perfect
mustn't I have been differing? mustn't you have been differing? mustn't he have been differing? mustn't we have been differing? mustn't you have been differing? mustn't they have been differing?