must scoff
Regular verb: scoff - scoffed- scoffed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must scoff
you must scoff
she must scoff
we must scoff
you must scoff
they must scoff 	I must be scoffing
you must be scoffing
she must be scoffing
we must be scoffing
you must be scoffing
they must be scoffing	I must have scoffed
you must have scoffed
she must have scoffed
we must have scoffed
you must have scoffed
they must have scoffed	I must have been scoffing
you must have been scoffing
she must have been scoffing
we must have been scoffing
you must have been scoffing
they must have been scoffing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't scoff
you mustn't scoff
she mustn't scoff
we mustn't scoff
you mustn't scoff
they mustn't scoff 	I mustn't be scoffing
you mustn't be scoffing
she mustn't be scoffing
we mustn't be scoffing
you mustn't be scoffing
they mustn't be scoffing	I mustn't have scoffed
you mustn't have scoffed
she mustn't have scoffed
we mustn't have scoffed
you mustn't have scoffed
they mustn't have scoffed	I mustn't have been scoffing
you mustn't have been scoffing
she mustn't have been scoffing
we mustn't have been scoffing
you mustn't have been scoffing
they mustn't have been scoffing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I scoff?
must you scoff?
must she scoff?
must we scoff?
must you scoff?
must they scoff? 	must I be scoffing?
must you be scoffing?
must she be scoffing?
must we be scoffing?
must you be scoffing?
must they be scoffing? 	must I have scoffed?
must you have scoffed?
must she have scoffed?
must we have scoffed?
must you have scoffed?
must they have scoffed? 	must I have been scoffing?
must you have been scoffing?
must she have been scoffing?
must we have been scoffing?
must you have been scoffing?
must they have been scoffing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I scoff?
mustn't you scoff?
mustn't she scoff?
mustn't we scoff?
mustn't you scoff?
mustn't they scoff? 	mustn't I be scoffing?
mustn't you be scoffing?
mustn't she be scoffing?
mustn't we be scoffing?
mustn't you be scoffing?
mustn't they be scoffing? 	mustn't I have scoffed?
mustn't you have scoffed?
mustn't she have scoffed?
mustn't we have scoffed?
mustn't you have scoffed?
mustn't they have scoffed? 	mustn't I have been scoffing?
mustn't you have been scoffing?
mustn't she have been scoffing?
mustn't we have been scoffing?
mustn't you have been scoffing?
mustn't they have been scoffing?