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