I could solve you could solve he could solve we could solve you could solve they could solve
Forma con V-ing
I could be solving you could be solving he could be solving we could be solving you could be solving they could be solving
Perfecto
I could have solved you could have solved he could have solved we could have solved you could have solved they could have solved
Perfecto con V-ing
I could have been solving you could have been solving he could have been solving we could have been solving you could have been solving they could have been solving
Negación
Forma simple
I could not solve you could not solve he could not solve we could not solve you could not solve they could not solve
Forma con V-ing
I could not be solving you could not be solving he could not be solving we could not be solving you could not be solving they could not be solving
Perfecto
I could not have solved you could not have solved he could not have solved we could not have solved you could not have solved they could not have solved
Perfecto con V-ing
I could not have been solving you could not have been solving he could not have been solving we could not have been solving you could not have been solving they could not have been solving
Forma interrogativa
Forma simple
could I solve? could you solve? could he solve? could we solve? could you solve? could they solve?
Forma con V-ing
could I be solving? could you be solving? could he be solving? could we be solving? could you be solving? could they be solving?
Perfecto
could I have solved? could you have solved? could he have solved? could we have solved? could you have solved? could they have solved?
Perfecto con V-ing
could I have been solving? could you have been solving? could he have been solving? could we have been solving? could you have been solving? could they have been solving?
Forma interro-negativa
Forma simple
could I not solve? could you not solve? could he not solve? could we not solve? could you not solve? could they not solve?
Forma con V-ing
could I not be solving? could you not be solving? could he not be solving? could we not be solving? could you not be solving? could they not be solving?
Perfecto
could I not have solved? could you not have solved? could he not have solved? could we not have solved? could you not have solved? could they not have solved?
Perfecto con V-ing
could I not have been solving? could you not have been solving? could he not have been solving? could we not have been solving? could you not have been solving? could they not have been solving?