English verb conjugation
COULD BLACKEN

Regular verb: blacken - blackened - blackened

Affirmation

Simple form	V-ing form
I could blacken you could blacken he could blacken we could blacken you could blacken they could blacken	I could be blackening you could be blackening he could be blackening we could be blackening you could be blackening they could be blackening
Perfect	V-ing perfect
I could have blackened you could have blackened he could have blackened we could have blackened you could have blackened they could have blackened	I could have been blackening you could have been blackening he could have been blackening we could have been blackening you could have been blackening they could have been blackening

Negation

Simple form	V-ing form
I could not blacken you could not blacken he could not blacken we could not blacken you could not blacken they could not blacken	I could not be blackening you could not be blackening he could not be blackening we could not be blackening you could not be blackening they could not be blackening
Perfect	V-ing perfect
I could not have blackened you could not have blackened he could not have blackened we could not have blackened you could not have blackened they could not have blackened	I could not have been blackening you could not have been blackening he could not have been blackening we could not have been blackening you could not have been blackening they could not have been blackening

Interrogative form

Simple form	V-ing form
could I blacken? could you blacken? could he blacken? could we blacken? could you blacken? could they blacken?	could I be blackening? could you be blackening? could he be blackening? could we be blackening? could you be blackening? could they be blackening?
Perfect	V-ing perfect
could I have blackened? could you have blackened? could he have blackened? could we have blackened? could you have blackened? could they have blackened?	could I have been blackening? could you have been blackening? could he have been blackening? could we have been blackening? could you have been blackening? could they have been blackening?

Interro-negative form

Simple form	V-ing form
could I not blacken? could you not blacken? could he not blacken? could we not blacken? could you not blacken? could they not blacken?	could I not be blackening? could you not be blackening? could he not be blackening? could we not be blackening? could you not be blackening? could they not be blackening?
Perfect	V-ing perfect
could I not have blackened? could you not have blackened? could he not have blackened? could we not have blackened? could you not have blackened? could they not have blackened?	could I not have been blackening? could you not have been blackening? could he not have been blackening? could we not have been blackening? could you not have been blackening? could they not have been blackening?