I could witness you could witness he could witness we could witness you could witness they could witness
Forma com V-ing
I could be witnessing you could be witnessing he could be witnessing we could be witnessing you could be witnessing they could be witnessing
Perfeito
I could have witnessed you could have witnessed he could have witnessed we could have witnessed you could have witnessed they could have witnessed
Perfeito com V-ing
I could have been witnessing you could have been witnessing he could have been witnessing we could have been witnessing you could have been witnessing they could have been witnessing
Negação
Forma simple
I could not witness you could not witness he could not witness we could not witness you could not witness they could not witness
Forma com V-ing
I could not be witnessing you could not be witnessing he could not be witnessing we could not be witnessing you could not be witnessing they could not be witnessing
Perfeito
I could not have witnessed you could not have witnessed he could not have witnessed we could not have witnessed you could not have witnessed they could not have witnessed
Perfeito com V-ing
I could not have been witnessing you could not have been witnessing he could not have been witnessing we could not have been witnessing you could not have been witnessing they could not have been witnessing
Forma interrogativa
Forma simple
could I witness? could you witness? could he witness? could we witness? could you witness? could they witness?
Forma com V-ing
could I be witnessing? could you be witnessing? could he be witnessing? could we be witnessing? could you be witnessing? could they be witnessing?
Perfeito
could I have witnessed? could you have witnessed? could he have witnessed? could we have witnessed? could you have witnessed? could they have witnessed?
Perfeito com V-ing
could I have been witnessing? could you have been witnessing? could he have been witnessing? could we have been witnessing? could you have been witnessing? could they have been witnessing?
Forma interro-Negação
Forma simple
could I not witness? could you not witness? could he not witness? could we not witness? could you not witness? could they not witness?
Forma com V-ing
could I not be witnessing? could you not be witnessing? could he not be witnessing? could we not be witnessing? could you not be witnessing? could they not be witnessing?
Perfeito
could I not have witnessed? could you not have witnessed? could he not have witnessed? could we not have witnessed? could you not have witnessed? could they not have witnessed?
Perfeito com V-ing
could I not have been witnessing? could you not have been witnessing? could he not have been witnessing? could we not have been witnessing? could you not have been witnessing? could they not have been witnessing?