English verb conjugation
MUST UNBUTTON

Regular verb: unbutton - unbuttoned - unbuttoned

Affirmation

Simple form	V-ing form
I must unbutton you must unbutton he must unbutton we must unbutton you must unbutton they must unbutton	I must be unbuttoning you must be unbuttoning he must be unbuttoning we must be unbuttoning you must be unbuttoning they must be unbuttoning
Perfect	V-ing perfect
I must have unbuttoned you must have unbuttoned he must have unbuttoned we must have unbuttoned you must have unbuttoned they must have unbuttoned	I must have been unbuttoning you must have been unbuttoning he must have been unbuttoning we must have been unbuttoning you must have been unbuttoning they must have been unbuttoning

Negation

Simple form	V-ing form
I mustn't unbutton you mustn't unbutton he mustn't unbutton we mustn't unbutton you mustn't unbutton they mustn't unbutton	I mustn't be unbuttoning you mustn't be unbuttoning he mustn't be unbuttoning we mustn't be unbuttoning you mustn't be unbuttoning they mustn't be unbuttoning
Perfect	V-ing perfect
I mustn't have unbuttoned you mustn't have unbuttoned he mustn't have unbuttoned we mustn't have unbuttoned you mustn't have unbuttoned they mustn't have unbuttoned	I mustn't have been unbuttoning you mustn't have been unbuttoning he mustn't have been unbuttoning we mustn't have been unbuttoning you mustn't have been unbuttoning they mustn't have been unbuttoning

Interrogative form

Simple form	V-ing form
must I unbutton? must you unbutton? must he unbutton? must we unbutton? must you unbutton? must they unbutton?	must I be unbuttoning? must you be unbuttoning? must he be unbuttoning? must we be unbuttoning? must you be unbuttoning? must they be unbuttoning?
Perfect	V-ing perfect
must I have unbuttoned? must you have unbuttoned? must he have unbuttoned? must we have unbuttoned? must you have unbuttoned? must they have unbuttoned?	must I have been unbuttoning? must you have been unbuttoning? must he have been unbuttoning? must we have been unbuttoning? must you have been unbuttoning? must they have been unbuttoning?

Interro-negative form

Simple form	V-ing form
mustn't I unbutton? mustn't you unbutton? mustn't he unbutton? mustn't we unbutton? mustn't you unbutton? mustn't they unbutton?	mustn't I be unbuttoning? mustn't you be unbuttoning? mustn't he be unbuttoning? mustn't we be unbuttoning? mustn't you be unbuttoning? mustn't they be unbuttoning?
Perfect	V-ing perfect
mustn't I have unbuttoned? mustn't you have unbuttoned? mustn't he have unbuttoned? mustn't we have unbuttoned? mustn't you have unbuttoned? mustn't they have unbuttoned?	mustn't I have been unbuttoning? mustn't you have been unbuttoning? mustn't he have been unbuttoning? mustn't we have been unbuttoning? mustn't you have been unbuttoning? mustn't they have been unbuttoning?