I may certify you may certify he may certify we may certify you may certify they may certify
V-ing form
I may be certifying you may be certifying he may be certifying we may be certifying you may be certifying they may be certifying
Perfect
I may have certified you may have certified he 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 he may have been certifying we may have been certifying you may have been certifying they may have been certifying
Negation
Simple form
I mayn't certify you mayn't certify he mayn't certify we mayn't certify you mayn't certify they mayn't certify
V-ing form
I mayn't be certifying you mayn't be certifying he mayn't be certifying we mayn't be certifying you mayn't be certifying they mayn't be certifying
Perfect
I mayn't have certified you mayn't have certified he mayn't have certified we mayn't have certified you mayn't have certified they mayn't have certified
V-ing perfect
I mayn't have been certifying you mayn't have been certifying he mayn't have been certifying we mayn't have been certifying you mayn't have been certifying they mayn't have been certifying
Interrogative form
Simple form
may I certify? may you certify? may he certify? may we certify? may you certify? may they certify?
V-ing form
may I be certifying? may you be certifying? may he be certifying? may we be certifying? may you be certifying? may they be certifying?
Perfect
may I have certified? may you have certified? may he 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 he have been certifying? may we have been certifying? may you have been certifying? may they have been certifying?
Interro-negative form
Simple form
mayn't I certify? mayn't you certify? mayn't he certify? mayn't we certify? mayn't you certify? mayn't they certify?
V-ing form
mayn't I be certifying? mayn't you be certifying? mayn't he be certifying? mayn't we be certifying? mayn't you be certifying? mayn't they be certifying?
Perfect
mayn't I have certified? mayn't you have certified? mayn't he have certified? mayn't we have certified? mayn't you have certified? mayn't they have certified?
V-ing perfect
mayn't I have been certifying? mayn't you have been certifying? mayn't he have been certifying? mayn't we have been certifying? mayn't you have been certifying? mayn't they have been certifying?