English verb conjugation
COULD REFINE

Regular verb: refine - refined - refined

Affirmation

Simple form	V-ing form
I could refine you could refine she could refine we could refine you could refine they could refine	I could be refining you could be refining she could be refining we could be refining you could be refining they could be refining
Perfect	V-ing perfect
I could have refined you could have refined she could have refined we could have refined you could have refined they could have refined	I could have been refining you could have been refining she could have been refining we could have been refining you could have been refining they could have been refining

Negation

Simple form	V-ing form
I could not refine you could not refine she could not refine we could not refine you could not refine they could not refine	I could not be refining you could not be refining she could not be refining we could not be refining you could not be refining they could not be refining
Perfect	V-ing perfect
I could not have refined you could not have refined she could not have refined we could not have refined you could not have refined they could not have refined	I could not have been refining you could not have been refining she could not have been refining we could not have been refining you could not have been refining they could not have been refining

Interrogative form

Simple form	V-ing form
could I refine? could you refine? could she refine? could we refine? could you refine? could they refine?	could I be refining? could you be refining? could she be refining? could we be refining? could you be refining? could they be refining?
Perfect	V-ing perfect
could I have refined? could you have refined? could she have refined? could we have refined? could you have refined? could they have refined?	could I have been refining? could you have been refining? could she have been refining? could we have been refining? could you have been refining? could they have been refining?

Interro-negative form

Simple form	V-ing form
could I not refine? could you not refine? could she not refine? could we not refine? could you not refine? could they not refine?	could I not be refining? could you not be refining? could she not be refining? could we not be refining? could you not be refining? could they not be refining?
Perfect	V-ing perfect
could I not have refined? could you not have refined? could she not have refined? could we not have refined? could you not have refined? could they not have refined?	could I not have been refining? could you not have been refining? could she not have been refining? could we not have been refining? could you not have been refining? could they not have been refining?