must huff
Regular verb: huff - huffed- huffed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must huff
you must huff
she must huff
we must huff
you must huff
they must huff 	I must be huffing
you must be huffing
she must be huffing
we must be huffing
you must be huffing
they must be huffing	I must have huffed
you must have huffed
she must have huffed
we must have huffed
you must have huffed
they must have huffed	I must have been huffing
you must have been huffing
she must have been huffing
we must have been huffing
you must have been huffing
they must have been huffing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't huff
you mustn't huff
she mustn't huff
we mustn't huff
you mustn't huff
they mustn't huff 	I mustn't be huffing
you mustn't be huffing
she mustn't be huffing
we mustn't be huffing
you mustn't be huffing
they mustn't be huffing	I mustn't have huffed
you mustn't have huffed
she mustn't have huffed
we mustn't have huffed
you mustn't have huffed
they mustn't have huffed	I mustn't have been huffing
you mustn't have been huffing
she mustn't have been huffing
we mustn't have been huffing
you mustn't have been huffing
they mustn't have been huffing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I huff?
must you huff?
must she huff?
must we huff?
must you huff?
must they huff? 	must I be huffing?
must you be huffing?
must she be huffing?
must we be huffing?
must you be huffing?
must they be huffing? 	must I have huffed?
must you have huffed?
must she have huffed?
must we have huffed?
must you have huffed?
must they have huffed? 	must I have been huffing?
must you have been huffing?
must she have been huffing?
must we have been huffing?
must you have been huffing?
must they have been huffing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I huff?
mustn't you huff?
mustn't she huff?
mustn't we huff?
mustn't you huff?
mustn't they huff? 	mustn't I be huffing?
mustn't you be huffing?
mustn't she be huffing?
mustn't we be huffing?
mustn't you be huffing?
mustn't they be huffing? 	mustn't I have huffed?
mustn't you have huffed?
mustn't she have huffed?
mustn't we have huffed?
mustn't you have huffed?
mustn't they have huffed? 	mustn't I have been huffing?
mustn't you have been huffing?
mustn't she have been huffing?
mustn't we have been huffing?
mustn't you have been huffing?
mustn't they have been huffing?