I could prosper you could prosper he could prosper we could prosper you could prosper they could prosper
V-ing form
I could be prospering you could be prospering he could be prospering we could be prospering you could be prospering they could be prospering
Perfect
I could have prospered you could have prospered he could have prospered we could have prospered you could have prospered they could have prospered
V-ing perfect
I could have been prospering you could have been prospering he could have been prospering we could have been prospering you could have been prospering they could have been prospering
Negation
Simple form
I could not prosper you could not prosper he could not prosper we could not prosper you could not prosper they could not prosper
V-ing form
I could not be prospering you could not be prospering he could not be prospering we could not be prospering you could not be prospering they could not be prospering
Perfect
I could not have prospered you could not have prospered he could not have prospered we could not have prospered you could not have prospered they could not have prospered
V-ing perfect
I could not have been prospering you could not have been prospering he could not have been prospering we could not have been prospering you could not have been prospering they could not have been prospering
Interrogative form
Simple form
could I prosper? could you prosper? could he prosper? could we prosper? could you prosper? could they prosper?
V-ing form
could I be prospering? could you be prospering? could he be prospering? could we be prospering? could you be prospering? could they be prospering?
Perfect
could I have prospered? could you have prospered? could he have prospered? could we have prospered? could you have prospered? could they have prospered?
V-ing perfect
could I have been prospering? could you have been prospering? could he have been prospering? could we have been prospering? could you have been prospering? could they have been prospering?
Interro-negative form
Simple form
could I not prosper? could you not prosper? could he not prosper? could we not prosper? could you not prosper? could they not prosper?
V-ing form
could I not be prospering? could you not be prospering? could he not be prospering? could we not be prospering? could you not be prospering? could they not be prospering?
Perfect
could I not have prospered? could you not have prospered? could he not have prospered? could we not have prospered? could you not have prospered? could they not have prospered?
V-ing perfect
could I not have been prospering? could you not have been prospering? could he not have been prospering? could we not have been prospering? could you not have been prospering? could they not have been prospering?