I must fit you must fit he must fit we must fit you must fit they must fit
V-ing form
I must be fitting you must be fitting he must be fitting we must be fitting you must be fitting they must be fitting
Perfect
I must have fit, fitted you must have fit, fitted he must have fit, fitted we must have fit, fitted you must have fit, fitted they must have fit, fitted
V-ing perfect
I must have been fitting you must have been fitting he must have been fitting we must have been fitting you must have been fitting they must have been fitting
Negation
Simple form
I mustn't fit you mustn't fit he mustn't fit we mustn't fit you mustn't fit they mustn't fit
V-ing form
I mustn't be fitting you mustn't be fitting he mustn't be fitting we mustn't be fitting you mustn't be fitting they mustn't be fitting
Perfect
I mustn't have fit, fitted you mustn't have fit, fitted he mustn't have fit, fitted we mustn't have fit, fitted you mustn't have fit, fitted they mustn't have fit, fitted
V-ing perfect
I mustn't have been fitting you mustn't have been fitting he mustn't have been fitting we mustn't have been fitting you mustn't have been fitting they mustn't have been fitting
Interrogative form
Simple form
must I fit? must you fit? must he fit? must we fit? must you fit? must they fit?
V-ing form
must I be fitting? must you be fitting? must he be fitting? must we be fitting? must you be fitting? must they be fitting?
Perfect
must I have fit, fitted? must you have fit, fitted? must he have fit, fitted? must we have fit, fitted? must you have fit, fitted? must they have fit, fitted?
V-ing perfect
must I have been fitting? must you have been fitting? must he have been fitting? must we have been fitting? must you have been fitting? must they have been fitting?
Interro-negative form
Simple form
mustn't I fit? mustn't you fit? mustn't he fit? mustn't we fit? mustn't you fit? mustn't they fit?
V-ing form
mustn't I be fitting? mustn't you be fitting? mustn't he be fitting? mustn't we be fitting? mustn't you be fitting? mustn't they be fitting?
Perfect
mustn't I have fit, fitted? mustn't you have fit, fitted? mustn't he have fit, fitted? mustn't we have fit, fitted? mustn't you have fit, fitted? mustn't they have fit, fitted?
V-ing perfect
mustn't I have been fitting? mustn't you have been fitting? mustn't he have been fitting? mustn't we have been fitting? mustn't you have been fitting? mustn't they have been fitting?