must fag
Regular verb: fag - fagged- fagged

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must fag
you must fag
he must fag
we must fag
you must fag
they must fag 	I must be fagging
you must be fagging
he must be fagging
we must be fagging
you must be fagging
they must be fagging	I must have fagged
you must have fagged
he must have fagged
we must have fagged
you must have fagged
they must have fagged	I must have been fagging
you must have been fagging
he must have been fagging
we must have been fagging
you must have been fagging
they must have been fagging	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't fag
you mustn't fag
he mustn't fag
we mustn't fag
you mustn't fag
they mustn't fag 	I mustn't be fagging
you mustn't be fagging
he mustn't be fagging
we mustn't be fagging
you mustn't be fagging
they mustn't be fagging	I mustn't have fagged
you mustn't have fagged
he mustn't have fagged
we mustn't have fagged
you mustn't have fagged
they mustn't have fagged	I mustn't have been fagging
you mustn't have been fagging
he mustn't have been fagging
we mustn't have been fagging
you mustn't have been fagging
they mustn't have been fagging	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I fag?
must you fag?
must he fag?
must we fag?
must you fag?
must they fag? 	must I be fagging?
must you be fagging?
must he be fagging?
must we be fagging?
must you be fagging?
must they be fagging? 	must I have fagged?
must you have fagged?
must he have fagged?
must we have fagged?
must you have fagged?
must they have fagged? 	must I have been fagging?
must you have been fagging?
must he have been fagging?
must we have been fagging?
must you have been fagging?
must they have been fagging? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I fag?
mustn't you fag?
mustn't he fag?
mustn't we fag?
mustn't you fag?
mustn't they fag? 	mustn't I be fagging?
mustn't you be fagging?
mustn't he be fagging?
mustn't we be fagging?
mustn't you be fagging?
mustn't they be fagging? 	mustn't I have fagged?
mustn't you have fagged?
mustn't he have fagged?
mustn't we have fagged?
mustn't you have fagged?
mustn't they have fagged? 	mustn't I have been fagging?
mustn't you have been fagging?
mustn't he have been fagging?
mustn't we have been fagging?
mustn't you have been fagging?
mustn't they have been fagging?