I could sightsee you could sightsee he could sightsee we could sightsee you could sightsee they could sightsee
Forma com V-ing
I could be sightseeing you could be sightseeing he could be sightseeing we could be sightseeing you could be sightseeing they could be sightseeing
Perfeito
I could have sightseed you could have sightseed he could have sightseed we could have sightseed you could have sightseed they could have sightseed
Perfeito com V-ing
I could have been sightseeing you could have been sightseeing he could have been sightseeing we could have been sightseeing you could have been sightseeing they could have been sightseeing
Negação
Forma simple
I could not sightsee you could not sightsee he could not sightsee we could not sightsee you could not sightsee they could not sightsee
Forma com V-ing
I could not be sightseeing you could not be sightseeing he could not be sightseeing we could not be sightseeing you could not be sightseeing they could not be sightseeing
Perfeito
I could not have sightseed you could not have sightseed he could not have sightseed we could not have sightseed you could not have sightseed they could not have sightseed
Perfeito com V-ing
I could not have been sightseeing you could not have been sightseeing he could not have been sightseeing we could not have been sightseeing you could not have been sightseeing they could not have been sightseeing
Forma interrogativa
Forma simple
could I sightsee? could you sightsee? could he sightsee? could we sightsee? could you sightsee? could they sightsee?
Forma com V-ing
could I be sightseeing? could you be sightseeing? could he be sightseeing? could we be sightseeing? could you be sightseeing? could they be sightseeing?
Perfeito
could I have sightseed? could you have sightseed? could he have sightseed? could we have sightseed? could you have sightseed? could they have sightseed?
Perfeito com V-ing
could I have been sightseeing? could you have been sightseeing? could he have been sightseeing? could we have been sightseeing? could you have been sightseeing? could they have been sightseeing?
Forma interro-Negação
Forma simple
could I not sightsee? could you not sightsee? could he not sightsee? could we not sightsee? could you not sightsee? could they not sightsee?
Forma com V-ing
could I not be sightseeing? could you not be sightseeing? could he not be sightseeing? could we not be sightseeing? could you not be sightseeing? could they not be sightseeing?
Perfeito
could I not have sightseed? could you not have sightseed? could he not have sightseed? could we not have sightseed? could you not have sightseed? could they not have sightseed?
Perfeito com V-ing
could I not have been sightseeing? could you not have been sightseeing? could he not have been sightseeing? could we not have been sightseeing? could you not have been sightseeing? could they not have been sightseeing?