I could author you could author he could author we could author you could author they could author
Forma com V-ing
I could be authoring you could be authoring he could be authoring we could be authoring you could be authoring they could be authoring
Perfeito
I could have authored you could have authored he could have authored we could have authored you could have authored they could have authored
Perfeito com V-ing
I could have been authoring you could have been authoring he could have been authoring we could have been authoring you could have been authoring they could have been authoring
Negação
Forma simple
I couldn't author you couldn't author he couldn't author we couldn't author you couldn't author they couldn't author
Forma com V-ing
I couldn't be authoring you couldn't be authoring he couldn't be authoring we couldn't be authoring you couldn't be authoring they couldn't be authoring
Perfeito
I couldn't have authored you couldn't have authored he couldn't have authored we couldn't have authored you couldn't have authored they couldn't have authored
Perfeito com V-ing
I couldn't have been authoring you couldn't have been authoring he couldn't have been authoring we couldn't have been authoring you couldn't have been authoring they couldn't have been authoring
Forma interrogativa
Forma simple
could I author? could you author? could he author? could we author? could you author? could they author?
Forma com V-ing
could I be authoring? could you be authoring? could he be authoring? could we be authoring? could you be authoring? could they be authoring?
Perfeito
could I have authored? could you have authored? could he have authored? could we have authored? could you have authored? could they have authored?
Perfeito com V-ing
could I have been authoring? could you have been authoring? could he have been authoring? could we have been authoring? could you have been authoring? could they have been authoring?
Forma interro-Negação
Forma simple
couldn't I author? couldn't you author? couldn't he author? couldn't we author? couldn't you author? couldn't they author?
Forma com V-ing
couldn't I be authoring? couldn't you be authoring? couldn't he be authoring? couldn't we be authoring? couldn't you be authoring? couldn't they be authoring?
Perfeito
couldn't I have authored? couldn't you have authored? couldn't he have authored? couldn't we have authored? couldn't you have authored? couldn't they have authored?
Perfeito com V-ing
couldn't I have been authoring? couldn't you have been authoring? couldn't he have been authoring? couldn't we have been authoring? couldn't you have been authoring? couldn't they have been authoring?