I could bill you could bill he could bill we could bill you could bill they could bill
Forma com V-ing
I could be billing you could be billing he could be billing we could be billing you could be billing they could be billing
Perfeito
I could have billed you could have billed he could have billed we could have billed you could have billed they could have billed
Perfeito com V-ing
I could have been billing you could have been billing he could have been billing we could have been billing you could have been billing they could have been billing
Negação
Forma simple
I could not bill you could not bill he could not bill we could not bill you could not bill they could not bill
Forma com V-ing
I could not be billing you could not be billing he could not be billing we could not be billing you could not be billing they could not be billing
Perfeito
I could not have billed you could not have billed he could not have billed we could not have billed you could not have billed they could not have billed
Perfeito com V-ing
I could not have been billing you could not have been billing he could not have been billing we could not have been billing you could not have been billing they could not have been billing
Forma interrogativa
Forma simple
could I bill? could you bill? could he bill? could we bill? could you bill? could they bill?
Forma com V-ing
could I be billing? could you be billing? could he be billing? could we be billing? could you be billing? could they be billing?
Perfeito
could I have billed? could you have billed? could he have billed? could we have billed? could you have billed? could they have billed?
Perfeito com V-ing
could I have been billing? could you have been billing? could he have been billing? could we have been billing? could you have been billing? could they have been billing?
Forma interro-Negação
Forma simple
could I not bill? could you not bill? could he not bill? could we not bill? could you not bill? could they not bill?
Forma com V-ing
could I not be billing? could you not be billing? could he not be billing? could we not be billing? could you not be billing? could they not be billing?
Perfeito
could I not have billed? could you not have billed? could he not have billed? could we not have billed? could you not have billed? could they not have billed?
Perfeito com V-ing
could I not have been billing? could you not have been billing? could he not have been billing? could we not have been billing? could you not have been billing? could they not have been billing?