I can certify you can certify he can certify we can certify you can certify they can certify
Forma com V-ing
I can be certifying you can be certifying he can be certifying we can be certifying you can be certifying they can be certifying
Perfeito
I can have certified you can have certified he can have certified we can have certified you can have certified they can have certified
Perfeito com V-ing
I can have been certifying you can have been certifying he can have been certifying we can have been certifying you can have been certifying they can have been certifying
Negação
Forma simple
I cannot certify you cannot certify he cannot certify we cannot certify you cannot certify they cannot certify
Forma com V-ing
I cannot be certifying you cannot be certifying he cannot be certifying we cannot be certifying you cannot be certifying they cannot be certifying
Perfeito
I cannot have certified you cannot have certified he cannot have certified we cannot have certified you cannot have certified they cannot have certified
Perfeito com V-ing
I cannot have been certifying you cannot have been certifying he cannot have been certifying we cannot have been certifying you cannot have been certifying they cannot have been certifying
Forma interrogativa
Forma simple
can I certify? can you certify? can he certify? can we certify? can you certify? can they certify?
Forma com V-ing
can I be certifying? can you be certifying? can he be certifying? can we be certifying? can you be certifying? can they be certifying?
Perfeito
can I have certified? can you have certified? can he have certified? can we have certified? can you have certified? can they have certified?
Perfeito com V-ing
can I have been certifying? can you have been certifying? can he have been certifying? can we have been certifying? can you have been certifying? can they have been certifying?
Forma interro-Negação
Forma simple
can I not certify? can you not certify? can he not certify? can we not certify? can you not certify? can they not certify?
Forma com V-ing
can I not be certifying? can you not be certifying? can he not be certifying? can we not be certifying? can you not be certifying? can they not be certifying?
Perfeito
can I not have certified? can you not have certified? can he not have certified? can we not have certified? can you not have certified? can they not have certified?
Perfeito com V-ing
can I not have been certifying? can you not have been certifying? can he not have been certifying? can we not have been certifying? can you not have been certifying? can they not have been certifying?