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