I must differ you must differ she must differ we must differ you must differ they must differ
V-ing form
I must be differing you must be differing she must be differing we must be differing you must be differing they must be differing
Perfect
I must have differed you must have differed she 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 she 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 she 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 she 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 she 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 she 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 she differ? must we differ? must you differ? must they differ?
V-ing form
must I be differing? must you be differing? must she be differing? must we be differing? must you be differing? must they be differing?
Perfect
must I have differed? must you have differed? must she 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 she 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 she 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 she 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 she 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 she have been differing? mustn't we have been differing? mustn't you have been differing? mustn't they have been differing?