I could preface you could preface he could preface we could preface you could preface they could preface
Forma con V-ing
I could be prefacing you could be prefacing he could be prefacing we could be prefacing you could be prefacing they could be prefacing
Perfecto
I could have prefaced you could have prefaced he could have prefaced we could have prefaced you could have prefaced they could have prefaced
Perfecto con V-ing
I could have been prefacing you could have been prefacing he could have been prefacing we could have been prefacing you could have been prefacing they could have been prefacing
Negación
Forma simple
I could not preface you could not preface he could not preface we could not preface you could not preface they could not preface
Forma con V-ing
I could not be prefacing you could not be prefacing he could not be prefacing we could not be prefacing you could not be prefacing they could not be prefacing
Perfecto
I could not have prefaced you could not have prefaced he could not have prefaced we could not have prefaced you could not have prefaced they could not have prefaced
Perfecto con V-ing
I could not have been prefacing you could not have been prefacing he could not have been prefacing we could not have been prefacing you could not have been prefacing they could not have been prefacing
Forma interrogativa
Forma simple
could I preface? could you preface? could he preface? could we preface? could you preface? could they preface?
Forma con V-ing
could I be prefacing? could you be prefacing? could he be prefacing? could we be prefacing? could you be prefacing? could they be prefacing?
Perfecto
could I have prefaced? could you have prefaced? could he have prefaced? could we have prefaced? could you have prefaced? could they have prefaced?
Perfecto con V-ing
could I have been prefacing? could you have been prefacing? could he have been prefacing? could we have been prefacing? could you have been prefacing? could they have been prefacing?
Forma interro-negativa
Forma simple
could I not preface? could you not preface? could he not preface? could we not preface? could you not preface? could they not preface?
Forma con V-ing
could I not be prefacing? could you not be prefacing? could he not be prefacing? could we not be prefacing? could you not be prefacing? could they not be prefacing?
Perfecto
could I not have prefaced? could you not have prefaced? could he not have prefaced? could we not have prefaced? could you not have prefaced? could they not have prefaced?
Perfecto con V-ing
could I not have been prefacing? could you not have been prefacing? could he not have been prefacing? could we not have been prefacing? could you not have been prefacing? could they not have been prefacing?