I could teach you could teach he could teach we could teach you could teach they could teach
Forma com V-ing
I could be teaching you could be teaching he could be teaching we could be teaching you could be teaching they could be teaching
Perfeito
I could have taught you could have taught he could have taught we could have taught you could have taught they could have taught
Perfeito com V-ing
I could have been teaching you could have been teaching he could have been teaching we could have been teaching you could have been teaching they could have been teaching
Negação
Forma simple
I could not teach you could not teach he could not teach we could not teach you could not teach they could not teach
Forma com V-ing
I could not be teaching you could not be teaching he could not be teaching we could not be teaching you could not be teaching they could not be teaching
Perfeito
I could not have taught you could not have taught he could not have taught we could not have taught you could not have taught they could not have taught
Perfeito com V-ing
I could not have been teaching you could not have been teaching he could not have been teaching we could not have been teaching you could not have been teaching they could not have been teaching
Forma interrogativa
Forma simple
could I teach? could you teach? could he teach? could we teach? could you teach? could they teach?
Forma com V-ing
could I be teaching? could you be teaching? could he be teaching? could we be teaching? could you be teaching? could they be teaching?
Perfeito
could I have taught? could you have taught? could he have taught? could we have taught? could you have taught? could they have taught?
Perfeito com V-ing
could I have been teaching? could you have been teaching? could he have been teaching? could we have been teaching? could you have been teaching? could they have been teaching?
Forma interro-Negação
Forma simple
could I not teach? could you not teach? could he not teach? could we not teach? could you not teach? could they not teach?
Forma com V-ing
could I not be teaching? could you not be teaching? could he not be teaching? could we not be teaching? could you not be teaching? could they not be teaching?
Perfeito
could I not have taught? could you not have taught? could he not have taught? could we not have taught? could you not have taught? could they not have taught?
Perfeito com V-ing
could I not have been teaching? could you not have been teaching? could he not have been teaching? could we not have been teaching? could you not have been teaching? could they not have been teaching?