English verb conjugation
MUST OPEN

Regular verb: open - opened - opened

Affirmation

Simple form	V-ing form
I must open you must open he must open we must open you must open they must open	I must be opening you must be opening he must be opening we must be opening you must be opening they must be opening
Perfect	V-ing perfect
I must have opened you must have opened he must have opened we must have opened you must have opened they must have opened	I must have been opening you must have been opening he must have been opening we must have been opening you must have been opening they must have been opening

Negation

Simple form	V-ing form
I mustn't open you mustn't open he mustn't open we mustn't open you mustn't open they mustn't open	I mustn't be opening you mustn't be opening he mustn't be opening we mustn't be opening you mustn't be opening they mustn't be opening
Perfect	V-ing perfect
I mustn't have opened you mustn't have opened he mustn't have opened we mustn't have opened you mustn't have opened they mustn't have opened	I mustn't have been opening you mustn't have been opening he mustn't have been opening we mustn't have been opening you mustn't have been opening they mustn't have been opening

Interrogative form

Simple form	V-ing form
must I open? must you open? must he open? must we open? must you open? must they open?	must I be opening? must you be opening? must he be opening? must we be opening? must you be opening? must they be opening?
Perfect	V-ing perfect
must I have opened? must you have opened? must he have opened? must we have opened? must you have opened? must they have opened?	must I have been opening? must you have been opening? must he have been opening? must we have been opening? must you have been opening? must they have been opening?

Interro-negative form

Simple form	V-ing form
mustn't I open? mustn't you open? mustn't he open? mustn't we open? mustn't you open? mustn't they open?	mustn't I be opening? mustn't you be opening? mustn't he be opening? mustn't we be opening? mustn't you be opening? mustn't they be opening?
Perfect	V-ing perfect
mustn't I have opened? mustn't you have opened? mustn't he have opened? mustn't we have opened? mustn't you have opened? mustn't they have opened?	mustn't I have been opening? mustn't you have been opening? mustn't he have been opening? mustn't we have been opening? mustn't you have been opening? mustn't they have been opening?