I could open you could open he could open we could open you could open they could open
Forma con V-ing
I could be opening you could be opening he could be opening we could be opening you could be opening they could be opening
Perfecto
I could have opened you could have opened he could have opened we could have opened you could have opened they could have opened
Perfecto con V-ing
I could have been opening you could have been opening he could have been opening we could have been opening you could have been opening they could have been opening
Negación
Forma simple
I could not open you could not open he could not open we could not open you could not open they could not open
Forma con V-ing
I could not be opening you could not be opening he could not be opening we could not be opening you could not be opening they could not be opening
Perfecto
I could not have opened you could not have opened he could not have opened we could not have opened you could not have opened they could not have opened
Perfecto con V-ing
I could not have been opening you could not have been opening he could not have been opening we could not have been opening you could not have been opening they could not have been opening
Forma interrogativa
Forma simple
could I open? could you open? could he open? could we open? could you open? could they open?
Forma con V-ing
could I be opening? could you be opening? could he be opening? could we be opening? could you be opening? could they be opening?
Perfecto
could I have opened? could you have opened? could he have opened? could we have opened? could you have opened? could they have opened?
Perfecto con V-ing
could I have been opening? could you have been opening? could he have been opening? could we have been opening? could you have been opening? could they have been opening?
Forma interro-negativa
Forma simple
could I not open? could you not open? could he not open? could we not open? could you not open? could they not open?
Forma con V-ing
could I not be opening? could you not be opening? could he not be opening? could we not be opening? could you not be opening? could they not be opening?
Perfecto
could I not have opened? could you not have opened? could he not have opened? could we not have opened? could you not have opened? could they not have opened?
Perfecto con V-ing
could I not have been opening? could you not have been opening? could he not have been opening? could we not have been opening? could you not have been opening? could they not have been opening?