must stud
Regular verb: stud - studded- studded

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must stud
you must stud
she must stud
we must stud
you must stud
they must stud 	I must be studding
you must be studding
she must be studding
we must be studding
you must be studding
they must be studding	I must have studded
you must have studded
she must have studded
we must have studded
you must have studded
they must have studded	I must have been studding
you must have been studding
she must have been studding
we must have been studding
you must have been studding
they must have been studding	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't stud
you mustn't stud
she mustn't stud
we mustn't stud
you mustn't stud
they mustn't stud 	I mustn't be studding
you mustn't be studding
she mustn't be studding
we mustn't be studding
you mustn't be studding
they mustn't be studding	I mustn't have studded
you mustn't have studded
she mustn't have studded
we mustn't have studded
you mustn't have studded
they mustn't have studded	I mustn't have been studding
you mustn't have been studding
she mustn't have been studding
we mustn't have been studding
you mustn't have been studding
they mustn't have been studding	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I stud?
must you stud?
must she stud?
must we stud?
must you stud?
must they stud? 	must I be studding?
must you be studding?
must she be studding?
must we be studding?
must you be studding?
must they be studding? 	must I have studded?
must you have studded?
must she have studded?
must we have studded?
must you have studded?
must they have studded? 	must I have been studding?
must you have been studding?
must she have been studding?
must we have been studding?
must you have been studding?
must they have been studding? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I stud?
mustn't you stud?
mustn't she stud?
mustn't we stud?
mustn't you stud?
mustn't they stud? 	mustn't I be studding?
mustn't you be studding?
mustn't she be studding?
mustn't we be studding?
mustn't you be studding?
mustn't they be studding? 	mustn't I have studded?
mustn't you have studded?
mustn't she have studded?
mustn't we have studded?
mustn't you have studded?
mustn't they have studded? 	mustn't I have been studding?
mustn't you have been studding?
mustn't she have been studding?
mustn't we have been studding?
mustn't you have been studding?
mustn't they have been studding?