I could fail you could fail he could fail we could fail you could fail they could fail
Forma com V-ing
I could be failing you could be failing he could be failing we could be failing you could be failing they could be failing
Perfeito
I could have failed you could have failed he could have failed we could have failed you could have failed they could have failed
Perfeito com V-ing
I could have been failing you could have been failing he could have been failing we could have been failing you could have been failing they could have been failing
Negação
Forma simple
I could not fail you could not fail he could not fail we could not fail you could not fail they could not fail
Forma com V-ing
I could not be failing you could not be failing he could not be failing we could not be failing you could not be failing they could not be failing
Perfeito
I could not have failed you could not have failed he could not have failed we could not have failed you could not have failed they could not have failed
Perfeito com V-ing
I could not have been failing you could not have been failing he could not have been failing we could not have been failing you could not have been failing they could not have been failing
Forma interrogativa
Forma simple
could I fail? could you fail? could he fail? could we fail? could you fail? could they fail?
Forma com V-ing
could I be failing? could you be failing? could he be failing? could we be failing? could you be failing? could they be failing?
Perfeito
could I have failed? could you have failed? could he have failed? could we have failed? could you have failed? could they have failed?
Perfeito com V-ing
could I have been failing? could you have been failing? could he have been failing? could we have been failing? could you have been failing? could they have been failing?
Forma interro-Negação
Forma simple
could I not fail? could you not fail? could he not fail? could we not fail? could you not fail? could they not fail?
Forma com V-ing
could I not be failing? could you not be failing? could he not be failing? could we not be failing? could you not be failing? could they not be failing?
Perfeito
could I not have failed? could you not have failed? could he not have failed? could we not have failed? could you not have failed? could they not have failed?
Perfeito com V-ing
could I not have been failing? could you not have been failing? could he not have been failing? could we not have been failing? could you not have been failing? could they not have been failing?