I could whisper you could whisper he could whisper we could whisper you could whisper they could whisper
V-ing form
I could be whispering you could be whispering he could be whispering we could be whispering you could be whispering they could be whispering
Perfect
I could have whispered you could have whispered he could have whispered we could have whispered you could have whispered they could have whispered
V-ing perfect
I could have been whispering you could have been whispering he could have been whispering we could have been whispering you could have been whispering they could have been whispering
Negation
Simple form
I could not whisper you could not whisper he could not whisper we could not whisper you could not whisper they could not whisper
V-ing form
I could not be whispering you could not be whispering he could not be whispering we could not be whispering you could not be whispering they could not be whispering
Perfect
I could not have whispered you could not have whispered he could not have whispered we could not have whispered you could not have whispered they could not have whispered
V-ing perfect
I could not have been whispering you could not have been whispering he could not have been whispering we could not have been whispering you could not have been whispering they could not have been whispering
Interrogative form
Simple form
could I whisper? could you whisper? could he whisper? could we whisper? could you whisper? could they whisper?
V-ing form
could I be whispering? could you be whispering? could he be whispering? could we be whispering? could you be whispering? could they be whispering?
Perfect
could I have whispered? could you have whispered? could he have whispered? could we have whispered? could you have whispered? could they have whispered?
V-ing perfect
could I have been whispering? could you have been whispering? could he have been whispering? could we have been whispering? could you have been whispering? could they have been whispering?
Interro-negative form
Simple form
could I not whisper? could you not whisper? could he not whisper? could we not whisper? could you not whisper? could they not whisper?
V-ing form
could I not be whispering? could you not be whispering? could he not be whispering? could we not be whispering? could you not be whispering? could they not be whispering?
Perfect
could I not have whispered? could you not have whispered? could he not have whispered? could we not have whispered? could you not have whispered? could they not have whispered?
V-ing perfect
could I not have been whispering? could you not have been whispering? could he not have been whispering? could we not have been whispering? could you not have been whispering? could they not have been whispering?