I may certify you may certify she may certify we may certify you may certify they may certify
V-ing form
I may be certifying you may be certifying she may be certifying we may be certifying you may be certifying they may be certifying
Perfect
I may have certified you may have certified she may have certified we may have certified you may have certified they may have certified
V-ing perfect
I may have been certifying you may have been certifying she may have been certifying we may have been certifying you may have been certifying they may have been certifying
Negation
Simple form
I may not certify you may not certify she may not certify we may not certify you may not certify they may not certify
V-ing form
I may not be certifying you may not be certifying she may not be certifying we may not be certifying you may not be certifying they may not be certifying
Perfect
I may not have certified you may not have certified she may not have certified we may not have certified you may not have certified they may not have certified
V-ing perfect
I may not have been certifying you may not have been certifying she may not have been certifying we may not have been certifying you may not have been certifying they may not have been certifying
Interrogative form
Simple form
may I certify? may you certify? may she certify? may we certify? may you certify? may they certify?
V-ing form
may I be certifying? may you be certifying? may she be certifying? may we be certifying? may you be certifying? may they be certifying?
Perfect
may I have certified? may you have certified? may she have certified? may we have certified? may you have certified? may they have certified?
V-ing perfect
may I have been certifying? may you have been certifying? may she have been certifying? may we have been certifying? may you have been certifying? may they have been certifying?
Interro-negative form
Simple form
may I not certify? may you not certify? may she not certify? may we not certify? may you not certify? may they not certify?
V-ing form
may I not be certifying? may you not be certifying? may she not be certifying? may we not be certifying? may you not be certifying? may they not be certifying?
Perfect
may I not have certified? may you not have certified? may she not have certified? may we not have certified? may you not have certified? may they not have certified?
V-ing perfect
may I not have been certifying? may you not have been certifying? may she not have been certifying? may we not have been certifying? may you not have been certifying? may they not have been certifying?