Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could whiter you could whiter he could whiter we could whiter you could whiter they could whiter
V-ing form
I could be whitering you could be whitering he could be whitering we could be whitering you could be whitering they could be whitering
Perfect
I could have whitered you could have whitered he could have whitered we could have whitered you could have whitered they could have whitered
V-ing perfect
I could have been whitering you could have been whitering he could have been whitering we could have been whitering you could have been whitering they could have been whitering
Negation
Simple form
I could not whiter you could not whiter he could not whiter we could not whiter you could not whiter they could not whiter
V-ing form
I could not be whitering you could not be whitering he could not be whitering we could not be whitering you could not be whitering they could not be whitering
Perfect
I could not have whitered you could not have whitered he could not have whitered we could not have whitered you could not have whitered they could not have whitered
V-ing perfect
I could not have been whitering you could not have been whitering he could not have been whitering we could not have been whitering you could not have been whitering they could not have been whitering
Interrogative form
Simple form
could I whiter? could you whiter? could he whiter? could we whiter? could you whiter? could they whiter?
V-ing form
could I be whitering? could you be whitering? could he be whitering? could we be whitering? could you be whitering? could they be whitering?
Perfect
could I have whitered? could you have whitered? could he have whitered? could we have whitered? could you have whitered? could they have whitered?
V-ing perfect
could I have been whitering? could you have been whitering? could he have been whitering? could we have been whitering? could you have been whitering? could they have been whitering?
Interro-negative form
Simple form
could I not whiter? could you not whiter? could he not whiter? could we not whiter? could you not whiter? could they not whiter?
V-ing form
could I not be whitering? could you not be whitering? could he not be whitering? could we not be whitering? could you not be whitering? could they not be whitering?
Perfect
could I not have whitered? could you not have whitered? could he not have whitered? could we not have whitered? could you not have whitered? could they not have whitered?
V-ing perfect
could I not have been whitering? could you not have been whitering? could he not have been whitering? could we not have been whitering? could you not have been whitering? could they not have been whitering?