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