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