I could birl you could birl she could birl we could birl you could birl they could birl
Forma con V-ing
I could be birling you could be birling she could be birling we could be birling you could be birling they could be birling
Perfecto
I could have birled you could have birled she could have birled we could have birled you could have birled they could have birled
Perfecto con V-ing
I could have been birling you could have been birling she could have been birling we could have been birling you could have been birling they could have been birling
Negación
Forma simple
I could not birl you could not birl she could not birl we could not birl you could not birl they could not birl
Forma con V-ing
I could not be birling you could not be birling she could not be birling we could not be birling you could not be birling they could not be birling
Perfecto
I could not have birled you could not have birled she could not have birled we could not have birled you could not have birled they could not have birled
Perfecto con V-ing
I could not have been birling you could not have been birling she could not have been birling we could not have been birling you could not have been birling they could not have been birling
Forma interrogativa
Forma simple
could I birl? could you birl? could she birl? could we birl? could you birl? could they birl?
Forma con V-ing
could I be birling? could you be birling? could she be birling? could we be birling? could you be birling? could they be birling?
Perfecto
could I have birled? could you have birled? could she have birled? could we have birled? could you have birled? could they have birled?
Perfecto con V-ing
could I have been birling? could you have been birling? could she have been birling? could we have been birling? could you have been birling? could they have been birling?
Forma interro-negativa
Forma simple
could I not birl? could you not birl? could she not birl? could we not birl? could you not birl? could they not birl?
Forma con V-ing
could I not be birling? could you not be birling? could she not be birling? could we not be birling? could you not be birling? could they not be birling?
Perfecto
could I not have birled? could you not have birled? could she not have birled? could we not have birled? could you not have birled? could they not have birled?
Perfecto con V-ing
could I not have been birling? could you not have been birling? could she not have been birling? could we not have been birling? could you not have been birling? could they not have been birling?