can certify
Regular verb: certify - certified- certified

Affirmation 	
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I can certify
you can certify
she can certify
we can certify
you can certify
they can certify 	I can be certifying
you can be certifying
she can be certifying
we can be certifying
you can be certifying
they can be certifying	I can have certified
you can have certified
she can have certified
we can have certified
you can have certified
they can have certified	I can have been certifying
you can have been certifying
she can have been certifying
we can have been certifying
you can have been certifying
they can have been certifying	

Negation 	
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I cannot certify
you cannot certify
she cannot certify
we cannot certify
you cannot certify
they cannot certify 	I cannot be certifying
you cannot be certifying
she cannot be certifying
we cannot be certifying
you cannot be certifying
they cannot be certifying	I cannot have certified
you cannot have certified
she cannot have certified
we cannot have certified
you cannot have certified
they cannot have certified	I cannot have been certifying
you cannot have been certifying
she cannot have been certifying
we cannot have been certifying
you cannot have been certifying
they cannot have been certifying	

Interrogative form 	
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can I certify?
can you certify?
can she certify?
can we certify?
can you certify?
can they certify? 	can I be certifying?
can you be certifying?
can she be certifying?
can we be certifying?
can you be certifying?
can they be certifying? 	can I have certified?
can you have certified?
can she have certified?
can we have certified?
can you have certified?
can they have certified? 	can I have been certifying?
can you have been certifying?
can she have been certifying?
can we have been certifying?
can you have been certifying?
can they have been certifying? 	

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