English verb conjugation
MUST ALTER

Regular verb: alter - altered - altered

Affirmation

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

Negation

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

Interrogative form

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

Interro-negative form

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