must sheaf
Regular verb: sheaf - sheafed- sheafed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must sheaf
you must sheaf
she must sheaf
we must sheaf
you must sheaf
they must sheaf 	I must be sheafing
you must be sheafing
she must be sheafing
we must be sheafing
you must be sheafing
they must be sheafing	I must have sheafed
you must have sheafed
she must have sheafed
we must have sheafed
you must have sheafed
they must have sheafed	I must have been sheafing
you must have been sheafing
she must have been sheafing
we must have been sheafing
you must have been sheafing
they must have been sheafing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't sheaf
you mustn't sheaf
she mustn't sheaf
we mustn't sheaf
you mustn't sheaf
they mustn't sheaf 	I mustn't be sheafing
you mustn't be sheafing
she mustn't be sheafing
we mustn't be sheafing
you mustn't be sheafing
they mustn't be sheafing	I mustn't have sheafed
you mustn't have sheafed
she mustn't have sheafed
we mustn't have sheafed
you mustn't have sheafed
they mustn't have sheafed	I mustn't have been sheafing
you mustn't have been sheafing
she mustn't have been sheafing
we mustn't have been sheafing
you mustn't have been sheafing
they mustn't have been sheafing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I sheaf?
must you sheaf?
must she sheaf?
must we sheaf?
must you sheaf?
must they sheaf? 	must I be sheafing?
must you be sheafing?
must she be sheafing?
must we be sheafing?
must you be sheafing?
must they be sheafing? 	must I have sheafed?
must you have sheafed?
must she have sheafed?
must we have sheafed?
must you have sheafed?
must they have sheafed? 	must I have been sheafing?
must you have been sheafing?
must she have been sheafing?
must we have been sheafing?
must you have been sheafing?
must they have been sheafing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I sheaf?
mustn't you sheaf?
mustn't she sheaf?
mustn't we sheaf?
mustn't you sheaf?
mustn't they sheaf? 	mustn't I be sheafing?
mustn't you be sheafing?
mustn't she be sheafing?
mustn't we be sheafing?
mustn't you be sheafing?
mustn't they be sheafing? 	mustn't I have sheafed?
mustn't you have sheafed?
mustn't she have sheafed?
mustn't we have sheafed?
mustn't you have sheafed?
mustn't they have sheafed? 	mustn't I have been sheafing?
mustn't you have been sheafing?
mustn't she have been sheafing?
mustn't we have been sheafing?
mustn't you have been sheafing?
mustn't they have been sheafing?