English verb conjugation
MUST BE

Irregular verb: be - was/were - been

Affirmation

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

Negation

Simple form	V-ing form
I must not be you must not be he must not be we must not be you must not be they must not be	I must not be being you must not be being he must not be being we must not be being you must not be being they must not be being
Perfect	V-ing perfect
I must not have been you must not have been he must not have been we must not have been you must not have been they must not have been	I must not have been being you must not have been being he must not have been being we must not have been being you must not have been being they must not have been being

Interrogative form

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

Interro-negative form

Simple form	V-ing form
must I not be? must you not be? must he not be? must we not be? must you not be? must they not be?	must I not be being? must you not be being? must he not be being? must we not be being? must you not be being? must they not be being?
Perfect	V-ing perfect
must I not have been? must you not have been? must he not have been? must we not have been? must you not have been? must they not have been?	must I not have been being? must you not have been being? must he not have been being? must we not have been being? must you not have been being? must they not have been being?