I could refute you could refute she could refute we could refute you could refute they could refute
V-ing form
I could be refuting you could be refuting she could be refuting we could be refuting you could be refuting they could be refuting
Perfect
I could have refuted you could have refuted she could have refuted we could have refuted you could have refuted they could have refuted
V-ing perfect
I could have been refuting you could have been refuting she could have been refuting we could have been refuting you could have been refuting they could have been refuting
Negation
Simple form
I could not refute you could not refute she could not refute we could not refute you could not refute they could not refute
V-ing form
I could not be refuting you could not be refuting she could not be refuting we could not be refuting you could not be refuting they could not be refuting
Perfect
I could not have refuted you could not have refuted she could not have refuted we could not have refuted you could not have refuted they could not have refuted
V-ing perfect
I could not have been refuting you could not have been refuting she could not have been refuting we could not have been refuting you could not have been refuting they could not have been refuting
Interrogative form
Simple form
could I refute? could you refute? could she refute? could we refute? could you refute? could they refute?
V-ing form
could I be refuting? could you be refuting? could she be refuting? could we be refuting? could you be refuting? could they be refuting?
Perfect
could I have refuted? could you have refuted? could she have refuted? could we have refuted? could you have refuted? could they have refuted?
V-ing perfect
could I have been refuting? could you have been refuting? could she have been refuting? could we have been refuting? could you have been refuting? could they have been refuting?
Interro-negative form
Simple form
could I not refute? could you not refute? could she not refute? could we not refute? could you not refute? could they not refute?
V-ing form
could I not be refuting? could you not be refuting? could she not be refuting? could we not be refuting? could you not be refuting? could they not be refuting?
Perfect
could I not have refuted? could you not have refuted? could she not have refuted? could we not have refuted? could you not have refuted? could they not have refuted?
V-ing perfect
could I not have been refuting? could you not have been refuting? could she not have been refuting? could we not have been refuting? could you not have been refuting? could they not have been refuting?