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 must not open you must not open he must not open we must not open you must not open they must not open	I must not be opening you must not be opening he must not be opening we must not be opening you must not be opening they must not be opening
Perfect	V-ing perfect
I must not have opened you must not have opened he must not have opened we must not have opened you must not have opened they must not have opened	I must not have been opening you must not have been opening he must not have been opening we must not have been opening you must not have been opening they must not 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
must I not open? must you not open? must he not open? must we not open? must you not open? must they not open?	must I not be opening? must you not be opening? must he not be opening? must we not be opening? must you not be opening? must they not be opening?
Perfect	V-ing perfect
must I not have opened? must you not have opened? must he not have opened? must we not have opened? must you not have opened? must they not have opened?	must I not have been opening? must you not have been opening? must he not have been opening? must we not have been opening? must you not have been opening? must they not have been opening?