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 couldn't ascertain you couldn't ascertain he couldn't ascertain we couldn't ascertain you couldn't ascertain they couldn't ascertain	I couldn't be ascertaining you couldn't be ascertaining he couldn't be ascertaining we couldn't be ascertaining you couldn't be ascertaining they couldn't be ascertaining
Perfeito	Perfeito com V-ing
I couldn't have ascertained you couldn't have ascertained he couldn't have ascertained we couldn't have ascertained you couldn't have ascertained they couldn't have ascertained	I couldn't have been ascertaining you couldn't have been ascertaining he couldn't have been ascertaining we couldn't have been ascertaining you couldn't have been ascertaining they couldn't 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
couldn't I ascertain? couldn't you ascertain? couldn't he ascertain? couldn't we ascertain? couldn't you ascertain? couldn't they ascertain?	couldn't I be ascertaining? couldn't you be ascertaining? couldn't he be ascertaining? couldn't we be ascertaining? couldn't you be ascertaining? couldn't they be ascertaining?
Perfeito	Perfeito com V-ing
couldn't I have ascertained? couldn't you have ascertained? couldn't he have ascertained? couldn't we have ascertained? couldn't you have ascertained? couldn't they have ascertained?	couldn't I have been ascertaining? couldn't you have been ascertaining? couldn't he have been ascertaining? couldn't we have been ascertaining? couldn't you have been ascertaining? couldn't they have been ascertaining?