I could regain you could regain she could regain we could regain you could regain they could regain
V-ing form
I could be regaining you could be regaining she could be regaining we could be regaining you could be regaining they could be regaining
Perfect
I could have regained you could have regained she could have regained we could have regained you could have regained they could have regained
V-ing perfect
I could have been regaining you could have been regaining she could have been regaining we could have been regaining you could have been regaining they could have been regaining
Negation
Simple form
I could not regain you could not regain she could not regain we could not regain you could not regain they could not regain
V-ing form
I could not be regaining you could not be regaining she could not be regaining we could not be regaining you could not be regaining they could not be regaining
Perfect
I could not have regained you could not have regained she could not have regained we could not have regained you could not have regained they could not have regained
V-ing perfect
I could not have been regaining you could not have been regaining she could not have been regaining we could not have been regaining you could not have been regaining they could not have been regaining
Interrogative form
Simple form
could I regain? could you regain? could she regain? could we regain? could you regain? could they regain?
V-ing form
could I be regaining? could you be regaining? could she be regaining? could we be regaining? could you be regaining? could they be regaining?
Perfect
could I have regained? could you have regained? could she have regained? could we have regained? could you have regained? could they have regained?
V-ing perfect
could I have been regaining? could you have been regaining? could she have been regaining? could we have been regaining? could you have been regaining? could they have been regaining?
Interro-negative form
Simple form
could I not regain? could you not regain? could she not regain? could we not regain? could you not regain? could they not regain?
V-ing form
could I not be regaining? could you not be regaining? could she not be regaining? could we not be regaining? could you not be regaining? could they not be regaining?
Perfect
could I not have regained? could you not have regained? could she not have regained? could we not have regained? could you not have regained? could they not have regained?
V-ing perfect
could I not have been regaining? could you not have been regaining? could she not have been regaining? could we not have been regaining? could you not have been regaining? could they not have been regaining?