I could err you could err he could err we could err you could err they could err
Forma com V-ing
I could be erring you could be erring he could be erring we could be erring you could be erring they could be erring
Perfeito
I could have erred you could have erred he could have erred we could have erred you could have erred they could have erred
Perfeito com V-ing
I could have been erring you could have been erring he could have been erring we could have been erring you could have been erring they could have been erring
Negação
Forma simple
I could not err you could not err he could not err we could not err you could not err they could not err
Forma com V-ing
I could not be erring you could not be erring he could not be erring we could not be erring you could not be erring they could not be erring
Perfeito
I could not have erred you could not have erred he could not have erred we could not have erred you could not have erred they could not have erred
Perfeito com V-ing
I could not have been erring you could not have been erring he could not have been erring we could not have been erring you could not have been erring they could not have been erring
Forma interrogativa
Forma simple
could I err? could you err? could he err? could we err? could you err? could they err?
Forma com V-ing
could I be erring? could you be erring? could he be erring? could we be erring? could you be erring? could they be erring?
Perfeito
could I have erred? could you have erred? could he have erred? could we have erred? could you have erred? could they have erred?
Perfeito com V-ing
could I have been erring? could you have been erring? could he have been erring? could we have been erring? could you have been erring? could they have been erring?
Forma interro-Negação
Forma simple
could I not err? could you not err? could he not err? could we not err? could you not err? could they not err?
Forma com V-ing
could I not be erring? could you not be erring? could he not be erring? could we not be erring? could you not be erring? could they not be erring?
Perfeito
could I not have erred? could you not have erred? could he not have erred? could we not have erred? could you not have erred? could they not have erred?
Perfeito com V-ing
could I not have been erring? could you not have been erring? could he not have been erring? could we not have been erring? could you not have been erring? could they not have been erring?