must chuff
Regular verb: chuff - chuffed- chuffed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must chuff
you must chuff
she must chuff
we must chuff
you must chuff
they must chuff 	I must be chuffing
you must be chuffing
she must be chuffing
we must be chuffing
you must be chuffing
they must be chuffing	I must have chuffed
you must have chuffed
she must have chuffed
we must have chuffed
you must have chuffed
they must have chuffed	I must have been chuffing
you must have been chuffing
she must have been chuffing
we must have been chuffing
you must have been chuffing
they must have been chuffing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not chuff
you must not chuff
she must not chuff
we must not chuff
you must not chuff
they must not chuff 	I must not be chuffing
you must not be chuffing
she must not be chuffing
we must not be chuffing
you must not be chuffing
they must not be chuffing	I must not have chuffed
you must not have chuffed
she must not have chuffed
we must not have chuffed
you must not have chuffed
they must not have chuffed	I must not have been chuffing
you must not have been chuffing
she must not have been chuffing
we must not have been chuffing
you must not have been chuffing
they must not have been chuffing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I chuff?
must you chuff?
must she chuff?
must we chuff?
must you chuff?
must they chuff? 	must I be chuffing?
must you be chuffing?
must she be chuffing?
must we be chuffing?
must you be chuffing?
must they be chuffing? 	must I have chuffed?
must you have chuffed?
must she have chuffed?
must we have chuffed?
must you have chuffed?
must they have chuffed? 	must I have been chuffing?
must you have been chuffing?
must she have been chuffing?
must we have been chuffing?
must you have been chuffing?
must they have been chuffing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not chuff?
must you not chuff?
must she not chuff?
must we not chuff?
must you not chuff?
must they not chuff? 	must I not be chuffing?
must you not be chuffing?
must she not be chuffing?
must we not be chuffing?
must you not be chuffing?
must they not be chuffing? 	must I not have chuffed?
must you not have chuffed?
must she not have chuffed?
must we not have chuffed?
must you not have chuffed?
must they not have chuffed? 	must I not have been chuffing?
must you not have been chuffing?
must she not have been chuffing?
must we not have been chuffing?
must you not have been chuffing?
must they not have been chuffing?