I could frog you could frog he could frog we could frog you could frog they could frog
Forma con V-ing
I could be froging you could be froging he could be froging we could be froging you could be froging they could be froging
Perfecto
I could have froged you could have froged he could have froged we could have froged you could have froged they could have froged
Perfecto con V-ing
I could have been froging you could have been froging he could have been froging we could have been froging you could have been froging they could have been froging
Negación
Forma simple
I could not frog you could not frog he could not frog we could not frog you could not frog they could not frog
Forma con V-ing
I could not be froging you could not be froging he could not be froging we could not be froging you could not be froging they could not be froging
Perfecto
I could not have froged you could not have froged he could not have froged we could not have froged you could not have froged they could not have froged
Perfecto con V-ing
I could not have been froging you could not have been froging he could not have been froging we could not have been froging you could not have been froging they could not have been froging
Forma interrogativa
Forma simple
could I frog? could you frog? could he frog? could we frog? could you frog? could they frog?
Forma con V-ing
could I be froging? could you be froging? could he be froging? could we be froging? could you be froging? could they be froging?
Perfecto
could I have froged? could you have froged? could he have froged? could we have froged? could you have froged? could they have froged?
Perfecto con V-ing
could I have been froging? could you have been froging? could he have been froging? could we have been froging? could you have been froging? could they have been froging?
Forma interro-negativa
Forma simple
could I not frog? could you not frog? could he not frog? could we not frog? could you not frog? could they not frog?
Forma con V-ing
could I not be froging? could you not be froging? could he not be froging? could we not be froging? could you not be froging? could they not be froging?
Perfecto
could I not have froged? could you not have froged? could he not have froged? could we not have froged? could you not have froged? could they not have froged?
Perfecto con V-ing
could I not have been froging? could you not have been froging? could he not have been froging? could we not have been froging? could you not have been froging? could they not have been froging?