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 couldn't blacken you couldn't blacken he couldn't blacken we couldn't blacken you couldn't blacken they couldn't blacken	I couldn't be blackening you couldn't be blackening he couldn't be blackening we couldn't be blackening you couldn't be blackening they couldn't be blackening
Perfect	V-ing perfect
I couldn't have blackened you couldn't have blackened he couldn't have blackened we couldn't have blackened you couldn't have blackened they couldn't have blackened	I couldn't have been blackening you couldn't have been blackening he couldn't have been blackening we couldn't have been blackening you couldn't have been blackening they couldn't 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
couldn't I blacken? couldn't you blacken? couldn't he blacken? couldn't we blacken? couldn't you blacken? couldn't they blacken?	couldn't I be blackening? couldn't you be blackening? couldn't he be blackening? couldn't we be blackening? couldn't you be blackening? couldn't they be blackening?
Perfect	V-ing perfect
couldn't I have blackened? couldn't you have blackened? couldn't he have blackened? couldn't we have blackened? couldn't you have blackened? couldn't they have blackened?	couldn't I have been blackening? couldn't you have been blackening? couldn't he have been blackening? couldn't we have been blackening? couldn't you have been blackening? couldn't they have been blackening?