English verb conjugation
MUST CERTIFY

Regular verb: certify - certified - certified

Affirmation

Simple form	V-ing form
I must certify you must certify she must certify we must certify you must certify they must certify	I must be certifying you must be certifying she must be certifying we must be certifying you must be certifying they must be certifying
Perfect	V-ing perfect
I must have certified you must have certified she must have certified we must have certified you must have certified they must have certified	I must have been certifying you must have been certifying she must have been certifying we must have been certifying you must have been certifying they must have been certifying

Negation

Simple form	V-ing form
I mustn't certify you mustn't certify she mustn't certify we mustn't certify you mustn't certify they mustn't certify	I mustn't be certifying you mustn't be certifying she mustn't be certifying we mustn't be certifying you mustn't be certifying they mustn't be certifying
Perfect	V-ing perfect
I mustn't have certified you mustn't have certified she mustn't have certified we mustn't have certified you mustn't have certified they mustn't have certified	I mustn't have been certifying you mustn't have been certifying she mustn't have been certifying we mustn't have been certifying you mustn't have been certifying they mustn't have been certifying

Interrogative form

Simple form	V-ing form
must I certify? must you certify? must she certify? must we certify? must you certify? must they certify?	must I be certifying? must you be certifying? must she be certifying? must we be certifying? must you be certifying? must they be certifying?
Perfect	V-ing perfect
must I have certified? must you have certified? must she have certified? must we have certified? must you have certified? must they have certified?	must I have been certifying? must you have been certifying? must she have been certifying? must we have been certifying? must you have been certifying? must they have been certifying?

Interro-negative form

Simple form	V-ing form
mustn't I certify? mustn't you certify? mustn't she certify? mustn't we certify? mustn't you certify? mustn't they certify?	mustn't I be certifying? mustn't you be certifying? mustn't she be certifying? mustn't we be certifying? mustn't you be certifying? mustn't they be certifying?
Perfect	V-ing perfect
mustn't I have certified? mustn't you have certified? mustn't she have certified? mustn't we have certified? mustn't you have certified? mustn't they have certified?	mustn't I have been certifying? mustn't you have been certifying? mustn't she have been certifying? mustn't we have been certifying? mustn't you have been certifying? mustn't they have been certifying?