I could sightsee you could sightsee he could sightsee we could sightsee you could sightsee they could sightsee
Forma con 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
Perfecto
I could have sightseed you could have sightseed he could have sightseed we could have sightseed you could have sightseed they could have sightseed
Perfecto con 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
Negación
Forma simple
I couldn't sightsee you couldn't sightsee he couldn't sightsee we couldn't sightsee you couldn't sightsee they couldn't sightsee
Forma con V-ing
I couldn't be sightseeing you couldn't be sightseeing he couldn't be sightseeing we couldn't be sightseeing you couldn't be sightseeing they couldn't be sightseeing
Perfecto
I couldn't have sightseed you couldn't have sightseed he couldn't have sightseed we couldn't have sightseed you couldn't have sightseed they couldn't have sightseed
Perfecto con V-ing
I couldn't have been sightseeing you couldn't have been sightseeing he couldn't have been sightseeing we couldn't have been sightseeing you couldn't have been sightseeing they couldn't 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 con 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?
Perfecto
could I have sightseed? could you have sightseed? could he have sightseed? could we have sightseed? could you have sightseed? could they have sightseed?
Perfecto con 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-negativa
Forma simple
couldn't I sightsee? couldn't you sightsee? couldn't he sightsee? couldn't we sightsee? couldn't you sightsee? couldn't they sightsee?
Forma con V-ing
couldn't I be sightseeing? couldn't you be sightseeing? couldn't he be sightseeing? couldn't we be sightseeing? couldn't you be sightseeing? couldn't they be sightseeing?
Perfecto
couldn't I have sightseed? couldn't you have sightseed? couldn't he have sightseed? couldn't we have sightseed? couldn't you have sightseed? couldn't they have sightseed?
Perfecto con V-ing
couldn't I have been sightseeing? couldn't you have been sightseeing? couldn't he have been sightseeing? couldn't we have been sightseeing? couldn't you have been sightseeing? couldn't they have been sightseeing?