must grunt
Verbo regular: grunt - grunted- grunted

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must grunt
you must grunt
he must grunt
we must grunt
you must grunt
they must grunt 	I must be grunting
you must be grunting
he must be grunting
we must be grunting
you must be grunting
they must be grunting	I must have grunted
you must have grunted
he must have grunted
we must have grunted
you must have grunted
they must have grunted	I must have been grunting
you must have been grunting
he must have been grunting
we must have been grunting
you must have been grunting
they must have been grunting	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I mustn't grunt
you mustn't grunt
he mustn't grunt
we mustn't grunt
you mustn't grunt
they mustn't grunt 	I mustn't be grunting
you mustn't be grunting
he mustn't be grunting
we mustn't be grunting
you mustn't be grunting
they mustn't be grunting	I mustn't have grunted
you mustn't have grunted
he mustn't have grunted
we mustn't have grunted
you mustn't have grunted
they mustn't have grunted	I mustn't have been grunting
you mustn't have been grunting
he mustn't have been grunting
we mustn't have been grunting
you mustn't have been grunting
they mustn't have been grunting	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I grunt?
must you grunt?
must he grunt?
must we grunt?
must you grunt?
must they grunt? 	must I be grunting?
must you be grunting?
must he be grunting?
must we be grunting?
must you be grunting?
must they be grunting? 	must I have grunted?
must you have grunted?
must he have grunted?
must we have grunted?
must you have grunted?
must they have grunted? 	must I have been grunting?
must you have been grunting?
must he have been grunting?
must we have been grunting?
must you have been grunting?
must they have been grunting? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
mustn't I grunt?
mustn't you grunt?
mustn't he grunt?
mustn't we grunt?
mustn't you grunt?
mustn't they grunt? 	mustn't I be grunting?
mustn't you be grunting?
mustn't he be grunting?
mustn't we be grunting?
mustn't you be grunting?
mustn't they be grunting? 	mustn't I have grunted?
mustn't you have grunted?
mustn't he have grunted?
mustn't we have grunted?
mustn't you have grunted?
mustn't they have grunted? 	mustn't I have been grunting?
mustn't you have been grunting?
mustn't he have been grunting?
mustn't we have been grunting?
mustn't you have been grunting?
mustn't they have been grunting?