must certify
Verbo regular: certify - certified- certified

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must certify
you must certify
he must certify
we must certify
you must certify
they must certify 	I must be certifying
you must be certifying
he must be certifying
we must be certifying
you must be certifying
they must be certifying	I must have certified
you must have certified
he 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
he must have been certifying
we must have been certifying
you must have been certifying
they must have been certifying	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must not certify
you must not certify
he must not certify
we must not certify
you must not certify
they must not certify 	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	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	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	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I certify?
must you certify?
must he certify?
must we certify?
must you certify?
must they certify? 	must I be certifying?
must you be certifying?
must he be certifying?
must we be certifying?
must you be certifying?
must they be certifying? 	must I have certified?
must you have certified?
must he 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 he have been certifying?
must we have been certifying?
must you have been certifying?
must they have been certifying? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I not certify?
must you not certify?
must he not certify?
must we not certify?
must you not certify?
must they not certify? 	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? 	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? 	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?