I could serve you could serve he could serve we could serve you could serve they could serve
Forma con V-ing
I could be serving you could be serving he could be serving we could be serving you could be serving they could be serving
Perfecto
I could have served you could have served he could have served we could have served you could have served they could have served
Perfecto con V-ing
I could have been serving you could have been serving he could have been serving we could have been serving you could have been serving they could have been serving
Negación
Forma simple
I could not serve you could not serve he could not serve we could not serve you could not serve they could not serve
Forma con V-ing
I could not be serving you could not be serving he could not be serving we could not be serving you could not be serving they could not be serving
Perfecto
I could not have served you could not have served he could not have served we could not have served you could not have served they could not have served
Perfecto con V-ing
I could not have been serving you could not have been serving he could not have been serving we could not have been serving you could not have been serving they could not have been serving
Forma interrogativa
Forma simple
could I serve? could you serve? could he serve? could we serve? could you serve? could they serve?
Forma con V-ing
could I be serving? could you be serving? could he be serving? could we be serving? could you be serving? could they be serving?
Perfecto
could I have served? could you have served? could he have served? could we have served? could you have served? could they have served?
Perfecto con V-ing
could I have been serving? could you have been serving? could he have been serving? could we have been serving? could you have been serving? could they have been serving?
Forma interro-negativa
Forma simple
could I not serve? could you not serve? could he not serve? could we not serve? could you not serve? could they not serve?
Forma con V-ing
could I not be serving? could you not be serving? could he not be serving? could we not be serving? could you not be serving? could they not be serving?
Perfecto
could I not have served? could you not have served? could he not have served? could we not have served? could you not have served? could they not have served?
Perfecto con V-ing
could I not have been serving? could you not have been serving? could he not have been serving? could we not have been serving? could you not have been serving? could they not have been serving?