must fox
Regular verb: fox - foxed- foxed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must fox
you must fox
he must fox
we must fox
you must fox
they must fox 	I must be foxing
you must be foxing
he must be foxing
we must be foxing
you must be foxing
they must be foxing	I must have foxed
you must have foxed
he must have foxed
we must have foxed
you must have foxed
they must have foxed	I must have been foxing
you must have been foxing
he must have been foxing
we must have been foxing
you must have been foxing
they must have been foxing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't fox
you mustn't fox
he mustn't fox
we mustn't fox
you mustn't fox
they mustn't fox 	I mustn't be foxing
you mustn't be foxing
he mustn't be foxing
we mustn't be foxing
you mustn't be foxing
they mustn't be foxing	I mustn't have foxed
you mustn't have foxed
he mustn't have foxed
we mustn't have foxed
you mustn't have foxed
they mustn't have foxed	I mustn't have been foxing
you mustn't have been foxing
he mustn't have been foxing
we mustn't have been foxing
you mustn't have been foxing
they mustn't have been foxing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I fox?
must you fox?
must he fox?
must we fox?
must you fox?
must they fox? 	must I be foxing?
must you be foxing?
must he be foxing?
must we be foxing?
must you be foxing?
must they be foxing? 	must I have foxed?
must you have foxed?
must he have foxed?
must we have foxed?
must you have foxed?
must they have foxed? 	must I have been foxing?
must you have been foxing?
must he have been foxing?
must we have been foxing?
must you have been foxing?
must they have been foxing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I fox?
mustn't you fox?
mustn't he fox?
mustn't we fox?
mustn't you fox?
mustn't they fox? 	mustn't I be foxing?
mustn't you be foxing?
mustn't he be foxing?
mustn't we be foxing?
mustn't you be foxing?
mustn't they be foxing? 	mustn't I have foxed?
mustn't you have foxed?
mustn't he have foxed?
mustn't we have foxed?
mustn't you have foxed?
mustn't they have foxed? 	mustn't I have been foxing?
mustn't you have been foxing?
mustn't he have been foxing?
mustn't we have been foxing?
mustn't you have been foxing?
mustn't they have been foxing?