I could swim you could swim he could swim we could swim you could swim they could swim
Forma con V-ing
I could be swimming you could be swimming he could be swimming we could be swimming you could be swimming they could be swimming
Perfecto
I could have swum you could have swum he could have swum we could have swum you could have swum they could have swum
Perfecto con V-ing
I could have been swimming you could have been swimming he could have been swimming we could have been swimming you could have been swimming they could have been swimming
Negación
Forma simple
I couldn't swim you couldn't swim he couldn't swim we couldn't swim you couldn't swim they couldn't swim
Forma con V-ing
I couldn't be swimming you couldn't be swimming he couldn't be swimming we couldn't be swimming you couldn't be swimming they couldn't be swimming
Perfecto
I couldn't have swum you couldn't have swum he couldn't have swum we couldn't have swum you couldn't have swum they couldn't have swum
Perfecto con V-ing
I couldn't have been swimming you couldn't have been swimming he couldn't have been swimming we couldn't have been swimming you couldn't have been swimming they couldn't have been swimming
Forma interrogativa
Forma simple
could I swim? could you swim? could he swim? could we swim? could you swim? could they swim?
Forma con V-ing
could I be swimming? could you be swimming? could he be swimming? could we be swimming? could you be swimming? could they be swimming?
Perfecto
could I have swum? could you have swum? could he have swum? could we have swum? could you have swum? could they have swum?
Perfecto con V-ing
could I have been swimming? could you have been swimming? could he have been swimming? could we have been swimming? could you have been swimming? could they have been swimming?
Forma interro-negativa
Forma simple
couldn't I swim? couldn't you swim? couldn't he swim? couldn't we swim? couldn't you swim? couldn't they swim?
Forma con V-ing
couldn't I be swimming? couldn't you be swimming? couldn't he be swimming? couldn't we be swimming? couldn't you be swimming? couldn't they be swimming?
Perfecto
couldn't I have swum? couldn't you have swum? couldn't he have swum? couldn't we have swum? couldn't you have swum? couldn't they have swum?
Perfecto con V-ing
couldn't I have been swimming? couldn't you have been swimming? couldn't he have been swimming? couldn't we have been swimming? couldn't you have been swimming? couldn't they have been swimming?