English verb conjugation
COULD CURTAIN

Regular verb: curtain - curtained - curtained

Affirmation

Simple form	V-ing form
I could curtain you could curtain he could curtain we could curtain you could curtain they could curtain	I could be curtaining you could be curtaining he could be curtaining we could be curtaining you could be curtaining they could be curtaining
Perfect	V-ing perfect
I could have curtained you could have curtained he could have curtained we could have curtained you could have curtained they could have curtained	I could have been curtaining you could have been curtaining he could have been curtaining we could have been curtaining you could have been curtaining they could have been curtaining

Negation

Simple form	V-ing form
I could not curtain you could not curtain he could not curtain we could not curtain you could not curtain they could not curtain	I could not be curtaining you could not be curtaining he could not be curtaining we could not be curtaining you could not be curtaining they could not be curtaining
Perfect	V-ing perfect
I could not have curtained you could not have curtained he could not have curtained we could not have curtained you could not have curtained they could not have curtained	I could not have been curtaining you could not have been curtaining he could not have been curtaining we could not have been curtaining you could not have been curtaining they could not have been curtaining

Interrogative form

Simple form	V-ing form
could I curtain? could you curtain? could he curtain? could we curtain? could you curtain? could they curtain?	could I be curtaining? could you be curtaining? could he be curtaining? could we be curtaining? could you be curtaining? could they be curtaining?
Perfect	V-ing perfect
could I have curtained? could you have curtained? could he have curtained? could we have curtained? could you have curtained? could they have curtained?	could I have been curtaining? could you have been curtaining? could he have been curtaining? could we have been curtaining? could you have been curtaining? could they have been curtaining?

Interro-negative form

Simple form	V-ing form
could I not curtain? could you not curtain? could he not curtain? could we not curtain? could you not curtain? could they not curtain?	could I not be curtaining? could you not be curtaining? could he not be curtaining? could we not be curtaining? could you not be curtaining? could they not be curtaining?
Perfect	V-ing perfect
could I not have curtained? could you not have curtained? could he not have curtained? could we not have curtained? could you not have curtained? could they not have curtained?	could I not have been curtaining? could you not have been curtaining? could he not have been curtaining? could we not have been curtaining? could you not have been curtaining? could they not have been curtaining?