must gaff
Regular verb: gaff - gaffed- gaffed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must gaff
you must gaff
he must gaff
we must gaff
you must gaff
they must gaff 	I must be gaffing
you must be gaffing
he must be gaffing
we must be gaffing
you must be gaffing
they must be gaffing	I must have gaffed
you must have gaffed
he must have gaffed
we must have gaffed
you must have gaffed
they must have gaffed	I must have been gaffing
you must have been gaffing
he must have been gaffing
we must have been gaffing
you must have been gaffing
they must have been gaffing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't gaff
you mustn't gaff
he mustn't gaff
we mustn't gaff
you mustn't gaff
they mustn't gaff 	I mustn't be gaffing
you mustn't be gaffing
he mustn't be gaffing
we mustn't be gaffing
you mustn't be gaffing
they mustn't be gaffing	I mustn't have gaffed
you mustn't have gaffed
he mustn't have gaffed
we mustn't have gaffed
you mustn't have gaffed
they mustn't have gaffed	I mustn't have been gaffing
you mustn't have been gaffing
he mustn't have been gaffing
we mustn't have been gaffing
you mustn't have been gaffing
they mustn't have been gaffing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I gaff?
must you gaff?
must he gaff?
must we gaff?
must you gaff?
must they gaff? 	must I be gaffing?
must you be gaffing?
must he be gaffing?
must we be gaffing?
must you be gaffing?
must they be gaffing? 	must I have gaffed?
must you have gaffed?
must he have gaffed?
must we have gaffed?
must you have gaffed?
must they have gaffed? 	must I have been gaffing?
must you have been gaffing?
must he have been gaffing?
must we have been gaffing?
must you have been gaffing?
must they have been gaffing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I gaff?
mustn't you gaff?
mustn't he gaff?
mustn't we gaff?
mustn't you gaff?
mustn't they gaff? 	mustn't I be gaffing?
mustn't you be gaffing?
mustn't he be gaffing?
mustn't we be gaffing?
mustn't you be gaffing?
mustn't they be gaffing? 	mustn't I have gaffed?
mustn't you have gaffed?
mustn't he have gaffed?
mustn't we have gaffed?
mustn't you have gaffed?
mustn't they have gaffed? 	mustn't I have been gaffing?
mustn't you have been gaffing?
mustn't he have been gaffing?
mustn't we have been gaffing?
mustn't you have been gaffing?
mustn't they have been gaffing?