I could build you could build she could build we could build you could build they could build
Forma con V-ing
I could be building you could be building she could be building we could be building you could be building they could be building
Perfecto
I could have built you could have built she could have built we could have built you could have built they could have built
Perfecto con V-ing
I could have been building you could have been building she could have been building we could have been building you could have been building they could have been building
Negación
Forma simple
I could not build you could not build she could not build we could not build you could not build they could not build
Forma con V-ing
I could not be building you could not be building she could not be building we could not be building you could not be building they could not be building
Perfecto
I could not have built you could not have built she could not have built we could not have built you could not have built they could not have built
Perfecto con V-ing
I could not have been building you could not have been building she could not have been building we could not have been building you could not have been building they could not have been building
Forma interrogativa
Forma simple
could I build? could you build? could she build? could we build? could you build? could they build?
Forma con V-ing
could I be building? could you be building? could she be building? could we be building? could you be building? could they be building?
Perfecto
could I have built? could you have built? could she have built? could we have built? could you have built? could they have built?
Perfecto con V-ing
could I have been building? could you have been building? could she have been building? could we have been building? could you have been building? could they have been building?
Forma interro-negativa
Forma simple
could I not build? could you not build? could she not build? could we not build? could you not build? could they not build?
Forma con V-ing
could I not be building? could you not be building? could she not be building? could we not be building? could you not be building? could they not be building?
Perfecto
could I not have built? could you not have built? could she not have built? could we not have built? could you not have built? could they not have built?
Perfecto con V-ing
could I not have been building? could you not have been building? could she not have been building? could we not have been building? could you not have been building? could they not have been building?