must box
Verbo regular: box - boxed- boxed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must box
you must box
he must box
we must box
you must box
they must box 	I must be boxing
you must be boxing
he must be boxing
we must be boxing
you must be boxing
they must be boxing	I must have boxed
you must have boxed
he must have boxed
we must have boxed
you must have boxed
they must have boxed	I must have been boxing
you must have been boxing
he must have been boxing
we must have been boxing
you must have been boxing
they must have been boxing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I mustn't box
you mustn't box
he mustn't box
we mustn't box
you mustn't box
they mustn't box 	I mustn't be boxing
you mustn't be boxing
he mustn't be boxing
we mustn't be boxing
you mustn't be boxing
they mustn't be boxing	I mustn't have boxed
you mustn't have boxed
he mustn't have boxed
we mustn't have boxed
you mustn't have boxed
they mustn't have boxed	I mustn't have been boxing
you mustn't have been boxing
he mustn't have been boxing
we mustn't have been boxing
you mustn't have been boxing
they mustn't have been boxing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I box?
must you box?
must he box?
must we box?
must you box?
must they box? 	must I be boxing?
must you be boxing?
must he be boxing?
must we be boxing?
must you be boxing?
must they be boxing? 	must I have boxed?
must you have boxed?
must he have boxed?
must we have boxed?
must you have boxed?
must they have boxed? 	must I have been boxing?
must you have been boxing?
must he have been boxing?
must we have been boxing?
must you have been boxing?
must they have been boxing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
mustn't I box?
mustn't you box?
mustn't he box?
mustn't we box?
mustn't you box?
mustn't they box? 	mustn't I be boxing?
mustn't you be boxing?
mustn't he be boxing?
mustn't we be boxing?
mustn't you be boxing?
mustn't they be boxing? 	mustn't I have boxed?
mustn't you have boxed?
mustn't he have boxed?
mustn't we have boxed?
mustn't you have boxed?
mustn't they have boxed? 	mustn't I have been boxing?
mustn't you have been boxing?
mustn't he have been boxing?
mustn't we have been boxing?
mustn't you have been boxing?
mustn't they have been boxing?