I could stack you could stack she could stack we could stack you could stack they could stack
Forma con V-ing
I could be stacking you could be stacking she could be stacking we could be stacking you could be stacking they could be stacking
Perfecto
I could have stacked you could have stacked she could have stacked we could have stacked you could have stacked they could have stacked
Perfecto con V-ing
I could have been stacking you could have been stacking she could have been stacking we could have been stacking you could have been stacking they could have been stacking
Negación
Forma simple
I couldn't stack you couldn't stack she couldn't stack we couldn't stack you couldn't stack they couldn't stack
Forma con V-ing
I couldn't be stacking you couldn't be stacking she couldn't be stacking we couldn't be stacking you couldn't be stacking they couldn't be stacking
Perfecto
I couldn't have stacked you couldn't have stacked she couldn't have stacked we couldn't have stacked you couldn't have stacked they couldn't have stacked
Perfecto con V-ing
I couldn't have been stacking you couldn't have been stacking she couldn't have been stacking we couldn't have been stacking you couldn't have been stacking they couldn't have been stacking
Forma interrogativa
Forma simple
could I stack? could you stack? could she stack? could we stack? could you stack? could they stack?
Forma con V-ing
could I be stacking? could you be stacking? could she be stacking? could we be stacking? could you be stacking? could they be stacking?
Perfecto
could I have stacked? could you have stacked? could she have stacked? could we have stacked? could you have stacked? could they have stacked?
Perfecto con V-ing
could I have been stacking? could you have been stacking? could she have been stacking? could we have been stacking? could you have been stacking? could they have been stacking?
Forma interro-negativa
Forma simple
couldn't I stack? couldn't you stack? couldn't she stack? couldn't we stack? couldn't you stack? couldn't they stack?
Forma con V-ing
couldn't I be stacking? couldn't you be stacking? couldn't she be stacking? couldn't we be stacking? couldn't you be stacking? couldn't they be stacking?
Perfecto
couldn't I have stacked? couldn't you have stacked? couldn't she have stacked? couldn't we have stacked? couldn't you have stacked? couldn't they have stacked?
Perfecto con V-ing
couldn't I have been stacking? couldn't you have been stacking? couldn't she have been stacking? couldn't we have been stacking? couldn't you have been stacking? couldn't they have been stacking?