I could blabber you could blabber he could blabber we could blabber you could blabber they could blabber
V-ing form
I could be blabbering you could be blabbering he could be blabbering we could be blabbering you could be blabbering they could be blabbering
Perfect
I could have blabbered you could have blabbered he could have blabbered we could have blabbered you could have blabbered they could have blabbered
V-ing perfect
I could have been blabbering you could have been blabbering he could have been blabbering we could have been blabbering you could have been blabbering they could have been blabbering
Negation
Simple form
I could not blabber you could not blabber he could not blabber we could not blabber you could not blabber they could not blabber
V-ing form
I could not be blabbering you could not be blabbering he could not be blabbering we could not be blabbering you could not be blabbering they could not be blabbering
Perfect
I could not have blabbered you could not have blabbered he could not have blabbered we could not have blabbered you could not have blabbered they could not have blabbered
V-ing perfect
I could not have been blabbering you could not have been blabbering he could not have been blabbering we could not have been blabbering you could not have been blabbering they could not have been blabbering
Interrogative form
Simple form
could I blabber? could you blabber? could he blabber? could we blabber? could you blabber? could they blabber?
V-ing form
could I be blabbering? could you be blabbering? could he be blabbering? could we be blabbering? could you be blabbering? could they be blabbering?
Perfect
could I have blabbered? could you have blabbered? could he have blabbered? could we have blabbered? could you have blabbered? could they have blabbered?
V-ing perfect
could I have been blabbering? could you have been blabbering? could he have been blabbering? could we have been blabbering? could you have been blabbering? could they have been blabbering?
Interro-negative form
Simple form
could I not blabber? could you not blabber? could he not blabber? could we not blabber? could you not blabber? could they not blabber?
V-ing form
could I not be blabbering? could you not be blabbering? could he not be blabbering? could we not be blabbering? could you not be blabbering? could they not be blabbering?
Perfect
could I not have blabbered? could you not have blabbered? could he not have blabbered? could we not have blabbered? could you not have blabbered? could they not have blabbered?
V-ing perfect
could I not have been blabbering? could you not have been blabbering? could he not have been blabbering? could we not have been blabbering? could you not have been blabbering? could they not have been blabbering?