must chaff
Regular verb: chaff - chaffed- chaffed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must chaff
you must chaff
he must chaff
we must chaff
you must chaff
they must chaff 	I must be chaffing
you must be chaffing
he must be chaffing
we must be chaffing
you must be chaffing
they must be chaffing	I must have chaffed
you must have chaffed
he must have chaffed
we must have chaffed
you must have chaffed
they must have chaffed	I must have been chaffing
you must have been chaffing
he must have been chaffing
we must have been chaffing
you must have been chaffing
they must have been chaffing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't chaff
you mustn't chaff
he mustn't chaff
we mustn't chaff
you mustn't chaff
they mustn't chaff 	I mustn't be chaffing
you mustn't be chaffing
he mustn't be chaffing
we mustn't be chaffing
you mustn't be chaffing
they mustn't be chaffing	I mustn't have chaffed
you mustn't have chaffed
he mustn't have chaffed
we mustn't have chaffed
you mustn't have chaffed
they mustn't have chaffed	I mustn't have been chaffing
you mustn't have been chaffing
he mustn't have been chaffing
we mustn't have been chaffing
you mustn't have been chaffing
they mustn't have been chaffing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I chaff?
must you chaff?
must he chaff?
must we chaff?
must you chaff?
must they chaff? 	must I be chaffing?
must you be chaffing?
must he be chaffing?
must we be chaffing?
must you be chaffing?
must they be chaffing? 	must I have chaffed?
must you have chaffed?
must he have chaffed?
must we have chaffed?
must you have chaffed?
must they have chaffed? 	must I have been chaffing?
must you have been chaffing?
must he have been chaffing?
must we have been chaffing?
must you have been chaffing?
must they have been chaffing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I chaff?
mustn't you chaff?
mustn't he chaff?
mustn't we chaff?
mustn't you chaff?
mustn't they chaff? 	mustn't I be chaffing?
mustn't you be chaffing?
mustn't he be chaffing?
mustn't we be chaffing?
mustn't you be chaffing?
mustn't they be chaffing? 	mustn't I have chaffed?
mustn't you have chaffed?
mustn't he have chaffed?
mustn't we have chaffed?
mustn't you have chaffed?
mustn't they have chaffed? 	mustn't I have been chaffing?
mustn't you have been chaffing?
mustn't he have been chaffing?
mustn't we have been chaffing?
mustn't you have been chaffing?
mustn't they have been chaffing?