Conjugação do verbo inglês
COULD ASCERTAIN

Verbo regular: ascertain - ascertained - ascertained

Afirmação

Forma simple	Forma com V-ing
I could ascertain you could ascertain he could ascertain we could ascertain you could ascertain they could ascertain	I could be ascertaining you could be ascertaining he could be ascertaining we could be ascertaining you could be ascertaining they could be ascertaining
Perfeito	Perfeito com V-ing
I could have ascertained you could have ascertained he could have ascertained we could have ascertained you could have ascertained they could have ascertained	I could have been ascertaining you could have been ascertaining he could have been ascertaining we could have been ascertaining you could have been ascertaining they could have been ascertaining

Negação

Forma simple	Forma com V-ing
I could not ascertain you could not ascertain he could not ascertain we could not ascertain you could not ascertain they could not ascertain	I could not be ascertaining you could not be ascertaining he could not be ascertaining we could not be ascertaining you could not be ascertaining they could not be ascertaining
Perfeito	Perfeito com V-ing
I could not have ascertained you could not have ascertained he could not have ascertained we could not have ascertained you could not have ascertained they could not have ascertained	I could not have been ascertaining you could not have been ascertaining he could not have been ascertaining we could not have been ascertaining you could not have been ascertaining they could not have been ascertaining

Forma interrogativa

Forma simple	Forma com V-ing
could I ascertain? could you ascertain? could he ascertain? could we ascertain? could you ascertain? could they ascertain?	could I be ascertaining? could you be ascertaining? could he be ascertaining? could we be ascertaining? could you be ascertaining? could they be ascertaining?
Perfeito	Perfeito com V-ing
could I have ascertained? could you have ascertained? could he have ascertained? could we have ascertained? could you have ascertained? could they have ascertained?	could I have been ascertaining? could you have been ascertaining? could he have been ascertaining? could we have been ascertaining? could you have been ascertaining? could they have been ascertaining?

Forma interro-Negação

Forma simple	Forma com V-ing
could I not ascertain? could you not ascertain? could he not ascertain? could we not ascertain? could you not ascertain? could they not ascertain?	could I not be ascertaining? could you not be ascertaining? could he not be ascertaining? could we not be ascertaining? could you not be ascertaining? could they not be ascertaining?
Perfeito	Perfeito com V-ing
could I not have ascertained? could you not have ascertained? could he not have ascertained? could we not have ascertained? could you not have ascertained? could they not have ascertained?	could I not have been ascertaining? could you not have been ascertaining? could he not have been ascertaining? could we not have been ascertaining? could you not have been ascertaining? could they not have been ascertaining?