English verb conjugation
COULD LIGHTEN

Regular verb: lighten - lightened - lightened

Affirmation

Simple form	V-ing form
I could lighten you could lighten he could lighten we could lighten you could lighten they could lighten	I could be lightening you could be lightening he could be lightening we could be lightening you could be lightening they could be lightening
Perfect	V-ing perfect
I could have lightened you could have lightened he could have lightened we could have lightened you could have lightened they could have lightened	I could have been lightening you could have been lightening he could have been lightening we could have been lightening you could have been lightening they could have been lightening

Negation

Simple form	V-ing form
I could not lighten you could not lighten he could not lighten we could not lighten you could not lighten they could not lighten	I could not be lightening you could not be lightening he could not be lightening we could not be lightening you could not be lightening they could not be lightening
Perfect	V-ing perfect
I could not have lightened you could not have lightened he could not have lightened we could not have lightened you could not have lightened they could not have lightened	I could not have been lightening you could not have been lightening he could not have been lightening we could not have been lightening you could not have been lightening they could not have been lightening

Interrogative form

Simple form	V-ing form
could I lighten? could you lighten? could he lighten? could we lighten? could you lighten? could they lighten?	could I be lightening? could you be lightening? could he be lightening? could we be lightening? could you be lightening? could they be lightening?
Perfect	V-ing perfect
could I have lightened? could you have lightened? could he have lightened? could we have lightened? could you have lightened? could they have lightened?	could I have been lightening? could you have been lightening? could he have been lightening? could we have been lightening? could you have been lightening? could they have been lightening?

Interro-negative form

Simple form	V-ing form
could I not lighten? could you not lighten? could he not lighten? could we not lighten? could you not lighten? could they not lighten?	could I not be lightening? could you not be lightening? could he not be lightening? could we not be lightening? could you not be lightening? could they not be lightening?
Perfect	V-ing perfect
could I not have lightened? could you not have lightened? could he not have lightened? could we not have lightened? could you not have lightened? could they not have lightened?	could I not have been lightening? could you not have been lightening? could he not have been lightening? could we not have been lightening? could you not have been lightening? could they not have been lightening?