I could sketch you could sketch she could sketch we could sketch you could sketch they could sketch
Forma con V-ing
I could be sketching you could be sketching she could be sketching we could be sketching you could be sketching they could be sketching
Perfecto
I could have sketched you could have sketched she could have sketched we could have sketched you could have sketched they could have sketched
Perfecto con V-ing
I could have been sketching you could have been sketching she could have been sketching we could have been sketching you could have been sketching they could have been sketching
Negación
Forma simple
I could not sketch you could not sketch she could not sketch we could not sketch you could not sketch they could not sketch
Forma con V-ing
I could not be sketching you could not be sketching she could not be sketching we could not be sketching you could not be sketching they could not be sketching
Perfecto
I could not have sketched you could not have sketched she could not have sketched we could not have sketched you could not have sketched they could not have sketched
Perfecto con V-ing
I could not have been sketching you could not have been sketching she could not have been sketching we could not have been sketching you could not have been sketching they could not have been sketching
Forma interrogativa
Forma simple
could I sketch? could you sketch? could she sketch? could we sketch? could you sketch? could they sketch?
Forma con V-ing
could I be sketching? could you be sketching? could she be sketching? could we be sketching? could you be sketching? could they be sketching?
Perfecto
could I have sketched? could you have sketched? could she have sketched? could we have sketched? could you have sketched? could they have sketched?
Perfecto con V-ing
could I have been sketching? could you have been sketching? could she have been sketching? could we have been sketching? could you have been sketching? could they have been sketching?
Forma interro-negativa
Forma simple
could I not sketch? could you not sketch? could she not sketch? could we not sketch? could you not sketch? could they not sketch?
Forma con V-ing
could I not be sketching? could you not be sketching? could she not be sketching? could we not be sketching? could you not be sketching? could they not be sketching?
Perfecto
could I not have sketched? could you not have sketched? could she not have sketched? could we not have sketched? could you not have sketched? could they not have sketched?
Perfecto con V-ing
could I not have been sketching? could you not have been sketching? could she not have been sketching? could we not have been sketching? could you not have been sketching? could they not have been sketching?