I could wither you could wither she could wither we could wither you could wither they could wither
V-ing form
I could be withering you could be withering she could be withering we could be withering you could be withering they could be withering
Perfect
I could have withered you could have withered she could have withered we could have withered you could have withered they could have withered
V-ing perfect
I could have been withering you could have been withering she could have been withering we could have been withering you could have been withering they could have been withering
Negation
Simple form
I could not wither you could not wither she could not wither we could not wither you could not wither they could not wither
V-ing form
I could not be withering you could not be withering she could not be withering we could not be withering you could not be withering they could not be withering
Perfect
I could not have withered you could not have withered she could not have withered we could not have withered you could not have withered they could not have withered
V-ing perfect
I could not have been withering you could not have been withering she could not have been withering we could not have been withering you could not have been withering they could not have been withering
Interrogative form
Simple form
could I wither? could you wither? could she wither? could we wither? could you wither? could they wither?
V-ing form
could I be withering? could you be withering? could she be withering? could we be withering? could you be withering? could they be withering?
Perfect
could I have withered? could you have withered? could she have withered? could we have withered? could you have withered? could they have withered?
V-ing perfect
could I have been withering? could you have been withering? could she have been withering? could we have been withering? could you have been withering? could they have been withering?
Interro-negative form
Simple form
could I not wither? could you not wither? could she not wither? could we not wither? could you not wither? could they not wither?
V-ing form
could I not be withering? could you not be withering? could she not be withering? could we not be withering? could you not be withering? could they not be withering?
Perfect
could I not have withered? could you not have withered? could she not have withered? could we not have withered? could you not have withered? could they not have withered?
V-ing perfect
could I not have been withering? could you not have been withering? could she not have been withering? could we not have been withering? could you not have been withering? could they not have been withering?