must master
Verbo regular: master - mastered- mastered

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must master
you must master
he must master
we must master
you must master
they must master 	I must be mastering
you must be mastering
he must be mastering
we must be mastering
you must be mastering
they must be mastering	I must have mastered
you must have mastered
he must have mastered
we must have mastered
you must have mastered
they must have mastered	I must have been mastering
you must have been mastering
he must have been mastering
we must have been mastering
you must have been mastering
they must have been mastering	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I mustn't master
you mustn't master
he mustn't master
we mustn't master
you mustn't master
they mustn't master 	I mustn't be mastering
you mustn't be mastering
he mustn't be mastering
we mustn't be mastering
you mustn't be mastering
they mustn't be mastering	I mustn't have mastered
you mustn't have mastered
he mustn't have mastered
we mustn't have mastered
you mustn't have mastered
they mustn't have mastered	I mustn't have been mastering
you mustn't have been mastering
he mustn't have been mastering
we mustn't have been mastering
you mustn't have been mastering
they mustn't have been mastering	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I master?
must you master?
must he master?
must we master?
must you master?
must they master? 	must I be mastering?
must you be mastering?
must he be mastering?
must we be mastering?
must you be mastering?
must they be mastering? 	must I have mastered?
must you have mastered?
must he have mastered?
must we have mastered?
must you have mastered?
must they have mastered? 	must I have been mastering?
must you have been mastering?
must he have been mastering?
must we have been mastering?
must you have been mastering?
must they have been mastering? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
mustn't I master?
mustn't you master?
mustn't he master?
mustn't we master?
mustn't you master?
mustn't they master? 	mustn't I be mastering?
mustn't you be mastering?
mustn't he be mastering?
mustn't we be mastering?
mustn't you be mastering?
mustn't they be mastering? 	mustn't I have mastered?
mustn't you have mastered?
mustn't he have mastered?
mustn't we have mastered?
mustn't you have mastered?
mustn't they have mastered? 	mustn't I have been mastering?
mustn't you have been mastering?
mustn't he have been mastering?
mustn't we have been mastering?
mustn't you have been mastering?
mustn't they have been mastering?