English verb conjugation
MUST STAIN

Regular verb: stain - stained - stained

Affirmation

Simple form	V-ing form
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
Perfect	V-ing perfect
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

Negation

Simple form	V-ing form
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
Perfect	V-ing perfect
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

Interrogative form

Simple form	V-ing form
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?
Perfect	V-ing perfect
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?

Interro-negative form

Simple form	V-ing form
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?
Perfect	V-ing perfect
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?