I could contest you could contest she could contest we could contest you could contest they could contest
V-ing form
I could be contesting you could be contesting she could be contesting we could be contesting you could be contesting they could be contesting
Perfect
I could have contested you could have contested she could have contested we could have contested you could have contested they could have contested
V-ing perfect
I could have been contesting you could have been contesting she could have been contesting we could have been contesting you could have been contesting they could have been contesting
Negation
Simple form
I could not contest you could not contest she could not contest we could not contest you could not contest they could not contest
V-ing form
I could not be contesting you could not be contesting she could not be contesting we could not be contesting you could not be contesting they could not be contesting
Perfect
I could not have contested you could not have contested she could not have contested we could not have contested you could not have contested they could not have contested
V-ing perfect
I could not have been contesting you could not have been contesting she could not have been contesting we could not have been contesting you could not have been contesting they could not have been contesting
Interrogative form
Simple form
could I contest? could you contest? could she contest? could we contest? could you contest? could they contest?
V-ing form
could I be contesting? could you be contesting? could she be contesting? could we be contesting? could you be contesting? could they be contesting?
Perfect
could I have contested? could you have contested? could she have contested? could we have contested? could you have contested? could they have contested?
V-ing perfect
could I have been contesting? could you have been contesting? could she have been contesting? could we have been contesting? could you have been contesting? could they have been contesting?
Interro-negative form
Simple form
could I not contest? could you not contest? could she not contest? could we not contest? could you not contest? could they not contest?
V-ing form
could I not be contesting? could you not be contesting? could she not be contesting? could we not be contesting? could you not be contesting? could they not be contesting?
Perfect
could I not have contested? could you not have contested? could she not have contested? could we not have contested? could you not have contested? could they not have contested?
V-ing perfect
could I not have been contesting? could you not have been contesting? could she not have been contesting? could we not have been contesting? could you not have been contesting? could they not have been contesting?