I could form you could form he could form we could form you could form they could form
Forma con V-ing
I could be forming you could be forming he could be forming we could be forming you could be forming they could be forming
Perfecto
I could have formed you could have formed he could have formed we could have formed you could have formed they could have formed
Perfecto con V-ing
I could have been forming you could have been forming he could have been forming we could have been forming you could have been forming they could have been forming
Negación
Forma simple
I could not form you could not form he could not form we could not form you could not form they could not form
Forma con V-ing
I could not be forming you could not be forming he could not be forming we could not be forming you could not be forming they could not be forming
Perfecto
I could not have formed you could not have formed he could not have formed we could not have formed you could not have formed they could not have formed
Perfecto con V-ing
I could not have been forming you could not have been forming he could not have been forming we could not have been forming you could not have been forming they could not have been forming
Forma interrogativa
Forma simple
could I form? could you form? could he form? could we form? could you form? could they form?
Forma con V-ing
could I be forming? could you be forming? could he be forming? could we be forming? could you be forming? could they be forming?
Perfecto
could I have formed? could you have formed? could he have formed? could we have formed? could you have formed? could they have formed?
Perfecto con V-ing
could I have been forming? could you have been forming? could he have been forming? could we have been forming? could you have been forming? could they have been forming?
Forma interro-negativa
Forma simple
could I not form? could you not form? could he not form? could we not form? could you not form? could they not form?
Forma con V-ing
could I not be forming? could you not be forming? could he not be forming? could we not be forming? could you not be forming? could they not be forming?
Perfecto
could I not have formed? could you not have formed? could he not have formed? could we not have formed? could you not have formed? could they not have formed?
Perfecto con V-ing
could I not have been forming? could you not have been forming? could he not have been forming? could we not have been forming? could you not have been forming? could they not have been forming?