English verb conjugation
COULD PREASCERTAIN

Regular verb: preascertain - preascertained - preascertained

Affirmation

Simple form	V-ing form
I could preascertain you could preascertain he could preascertain we could preascertain you could preascertain they could preascertain	I could be preascertaining you could be preascertaining he could be preascertaining we could be preascertaining you could be preascertaining they could be preascertaining
Perfect	V-ing perfect
I could have preascertained you could have preascertained he could have preascertained we could have preascertained you could have preascertained they could have preascertained	I could have been preascertaining you could have been preascertaining he could have been preascertaining we could have been preascertaining you could have been preascertaining they could have been preascertaining

Negation

Simple form	V-ing form
I couldn't preascertain you couldn't preascertain he couldn't preascertain we couldn't preascertain you couldn't preascertain they couldn't preascertain	I couldn't be preascertaining you couldn't be preascertaining he couldn't be preascertaining we couldn't be preascertaining you couldn't be preascertaining they couldn't be preascertaining
Perfect	V-ing perfect
I couldn't have preascertained you couldn't have preascertained he couldn't have preascertained we couldn't have preascertained you couldn't have preascertained they couldn't have preascertained	I couldn't have been preascertaining you couldn't have been preascertaining he couldn't have been preascertaining we couldn't have been preascertaining you couldn't have been preascertaining they couldn't have been preascertaining

Interrogative form

Simple form	V-ing form
could I preascertain? could you preascertain? could he preascertain? could we preascertain? could you preascertain? could they preascertain?	could I be preascertaining? could you be preascertaining? could he be preascertaining? could we be preascertaining? could you be preascertaining? could they be preascertaining?
Perfect	V-ing perfect
could I have preascertained? could you have preascertained? could he have preascertained? could we have preascertained? could you have preascertained? could they have preascertained?	could I have been preascertaining? could you have been preascertaining? could he have been preascertaining? could we have been preascertaining? could you have been preascertaining? could they have been preascertaining?

Interro-negative form

Simple form	V-ing form
couldn't I preascertain? couldn't you preascertain? couldn't he preascertain? couldn't we preascertain? couldn't you preascertain? couldn't they preascertain?	couldn't I be preascertaining? couldn't you be preascertaining? couldn't he be preascertaining? couldn't we be preascertaining? couldn't you be preascertaining? couldn't they be preascertaining?
Perfect	V-ing perfect
couldn't I have preascertained? couldn't you have preascertained? couldn't he have preascertained? couldn't we have preascertained? couldn't you have preascertained? couldn't they have preascertained?	couldn't I have been preascertaining? couldn't you have been preascertaining? couldn't he have been preascertaining? couldn't we have been preascertaining? couldn't you have been preascertaining? couldn't they have been preascertaining?