I could stiffen you could stiffen he could stiffen we could stiffen you could stiffen they could stiffen
Forma con V-ing
I could be stiffening you could be stiffening he could be stiffening we could be stiffening you could be stiffening they could be stiffening
Perfecto
I could have stiffened you could have stiffened he could have stiffened we could have stiffened you could have stiffened they could have stiffened
Perfecto con V-ing
I could have been stiffening you could have been stiffening he could have been stiffening we could have been stiffening you could have been stiffening they could have been stiffening
Negación
Forma simple
I could not stiffen you could not stiffen he could not stiffen we could not stiffen you could not stiffen they could not stiffen
Forma con V-ing
I could not be stiffening you could not be stiffening he could not be stiffening we could not be stiffening you could not be stiffening they could not be stiffening
Perfecto
I could not have stiffened you could not have stiffened he could not have stiffened we could not have stiffened you could not have stiffened they could not have stiffened
Perfecto con V-ing
I could not have been stiffening you could not have been stiffening he could not have been stiffening we could not have been stiffening you could not have been stiffening they could not have been stiffening
Forma interrogativa
Forma simple
could I stiffen? could you stiffen? could he stiffen? could we stiffen? could you stiffen? could they stiffen?
Forma con V-ing
could I be stiffening? could you be stiffening? could he be stiffening? could we be stiffening? could you be stiffening? could they be stiffening?
Perfecto
could I have stiffened? could you have stiffened? could he have stiffened? could we have stiffened? could you have stiffened? could they have stiffened?
Perfecto con V-ing
could I have been stiffening? could you have been stiffening? could he have been stiffening? could we have been stiffening? could you have been stiffening? could they have been stiffening?
Forma interro-negativa
Forma simple
could I not stiffen? could you not stiffen? could he not stiffen? could we not stiffen? could you not stiffen? could they not stiffen?
Forma con V-ing
could I not be stiffening? could you not be stiffening? could he not be stiffening? could we not be stiffening? could you not be stiffening? could they not be stiffening?
Perfecto
could I not have stiffened? could you not have stiffened? could he not have stiffened? could we not have stiffened? could you not have stiffened? could they not have stiffened?
Perfecto con V-ing
could I not have been stiffening? could you not have been stiffening? could he not have been stiffening? could we not have been stiffening? could you not have been stiffening? could they not have been stiffening?