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