must stain
Verbo regular: stain - stained- stained

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must stain
you must stain
he must stain
we must stain
you must stain
they must stain 	I must be staining
you must be staining
he must be staining
we must be staining
you must be staining
they must be staining	I must have stained
you must have stained
he must have stained
we must have stained
you must have stained
they must have stained	I must have been staining
you must have been staining
he must have been staining
we must have been staining
you must have been staining
they must have been staining	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I mustn't stain
you mustn't stain
he mustn't stain
we mustn't stain
you mustn't stain
they mustn't stain 	I mustn't be staining
you mustn't be staining
he mustn't be staining
we mustn't be staining
you mustn't be staining
they mustn't be staining	I mustn't have stained
you mustn't have stained
he mustn't have stained
we mustn't have stained
you mustn't have stained
they mustn't have stained	I mustn't have been staining
you mustn't have been staining
he mustn't have been staining
we mustn't have been staining
you mustn't have been staining
they mustn't have been staining	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I stain?
must you stain?
must he stain?
must we stain?
must you stain?
must they stain? 	must I be staining?
must you be staining?
must he be staining?
must we be staining?
must you be staining?
must they be staining? 	must I have stained?
must you have stained?
must he have stained?
must we have stained?
must you have stained?
must they have stained? 	must I have been staining?
must you have been staining?
must he have been staining?
must we have been staining?
must you have been staining?
must they have been staining? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
mustn't I stain?
mustn't you stain?
mustn't he stain?
mustn't we stain?
mustn't you stain?
mustn't they stain? 	mustn't I be staining?
mustn't you be staining?
mustn't he be staining?
mustn't we be staining?
mustn't you be staining?
mustn't they be staining? 	mustn't I have stained?
mustn't you have stained?
mustn't he have stained?
mustn't we have stained?
mustn't you have stained?
mustn't they have stained? 	mustn't I have been staining?
mustn't you have been staining?
mustn't he have been staining?
mustn't we have been staining?
mustn't you have been staining?
mustn't they have been staining?