I could japan you could japan he could japan we could japan you could japan they could japan
Forma con V-ing
I could be japaning you could be japaning he could be japaning we could be japaning you could be japaning they could be japaning
Perfecto
I could have japaned you could have japaned he could have japaned we could have japaned you could have japaned they could have japaned
Perfecto con V-ing
I could have been japaning you could have been japaning he could have been japaning we could have been japaning you could have been japaning they could have been japaning
Negación
Forma simple
I could not japan you could not japan he could not japan we could not japan you could not japan they could not japan
Forma con V-ing
I could not be japaning you could not be japaning he could not be japaning we could not be japaning you could not be japaning they could not be japaning
Perfecto
I could not have japaned you could not have japaned he could not have japaned we could not have japaned you could not have japaned they could not have japaned
Perfecto con V-ing
I could not have been japaning you could not have been japaning he could not have been japaning we could not have been japaning you could not have been japaning they could not have been japaning
Forma interrogativa
Forma simple
could I japan? could you japan? could he japan? could we japan? could you japan? could they japan?
Forma con V-ing
could I be japaning? could you be japaning? could he be japaning? could we be japaning? could you be japaning? could they be japaning?
Perfecto
could I have japaned? could you have japaned? could he have japaned? could we have japaned? could you have japaned? could they have japaned?
Perfecto con V-ing
could I have been japaning? could you have been japaning? could he have been japaning? could we have been japaning? could you have been japaning? could they have been japaning?
Forma interro-negativa
Forma simple
could I not japan? could you not japan? could he not japan? could we not japan? could you not japan? could they not japan?
Forma con V-ing
could I not be japaning? could you not be japaning? could he not be japaning? could we not be japaning? could you not be japaning? could they not be japaning?
Perfecto
could I not have japaned? could you not have japaned? could he not have japaned? could we not have japaned? could you not have japaned? could they not have japaned?
Perfecto con V-ing
could I not have been japaning? could you not have been japaning? could he not have been japaning? could we not have been japaning? could you not have been japaning? could they not have been japaning?