English verb conjugation
MUST PREVENT

Regular verb: prevent - prevented - prevented

Affirmation

Simple form	V-ing form
I must prevent you must prevent she must prevent we must prevent you must prevent they must prevent	I must be preventing you must be preventing she must be preventing we must be preventing you must be preventing they must be preventing
Perfect	V-ing perfect
I must have prevented you must have prevented she must have prevented we must have prevented you must have prevented they must have prevented	I must have been preventing you must have been preventing she must have been preventing we must have been preventing you must have been preventing they must have been preventing

Negation

Simple form	V-ing form
I must not prevent you must not prevent she must not prevent we must not prevent you must not prevent they must not prevent	I must not be preventing you must not be preventing she must not be preventing we must not be preventing you must not be preventing they must not be preventing
Perfect	V-ing perfect
I must not have prevented you must not have prevented she must not have prevented we must not have prevented you must not have prevented they must not have prevented	I must not have been preventing you must not have been preventing she must not have been preventing we must not have been preventing you must not have been preventing they must not have been preventing

Interrogative form

Simple form	V-ing form
must I prevent? must you prevent? must she prevent? must we prevent? must you prevent? must they prevent?	must I be preventing? must you be preventing? must she be preventing? must we be preventing? must you be preventing? must they be preventing?
Perfect	V-ing perfect
must I have prevented? must you have prevented? must she have prevented? must we have prevented? must you have prevented? must they have prevented?	must I have been preventing? must you have been preventing? must she have been preventing? must we have been preventing? must you have been preventing? must they have been preventing?

Interro-negative form

Simple form	V-ing form
must I not prevent? must you not prevent? must she not prevent? must we not prevent? must you not prevent? must they not prevent?	must I not be preventing? must you not be preventing? must she not be preventing? must we not be preventing? must you not be preventing? must they not be preventing?
Perfect	V-ing perfect
must I not have prevented? must you not have prevented? must she not have prevented? must we not have prevented? must you not have prevented? must they not have prevented?	must I not have been preventing? must you not have been preventing? must she not have been preventing? must we not have been preventing? must you not have been preventing? must they not have been preventing?