I could hail you could hail he could hail we could hail you could hail they could hail
V-ing form
I could be hailing you could be hailing he could be hailing we could be hailing you could be hailing they could be hailing
Perfect
I could have hailed you could have hailed he could have hailed we could have hailed you could have hailed they could have hailed
V-ing perfect
I could have been hailing you could have been hailing he could have been hailing we could have been hailing you could have been hailing they could have been hailing
Negation
Simple form
I could not hail you could not hail he could not hail we could not hail you could not hail they could not hail
V-ing form
I could not be hailing you could not be hailing he could not be hailing we could not be hailing you could not be hailing they could not be hailing
Perfect
I could not have hailed you could not have hailed he could not have hailed we could not have hailed you could not have hailed they could not have hailed
V-ing perfect
I could not have been hailing you could not have been hailing he could not have been hailing we could not have been hailing you could not have been hailing they could not have been hailing
Interrogative form
Simple form
could I hail? could you hail? could he hail? could we hail? could you hail? could they hail?
V-ing form
could I be hailing? could you be hailing? could he be hailing? could we be hailing? could you be hailing? could they be hailing?
Perfect
could I have hailed? could you have hailed? could he have hailed? could we have hailed? could you have hailed? could they have hailed?
V-ing perfect
could I have been hailing? could you have been hailing? could he have been hailing? could we have been hailing? could you have been hailing? could they have been hailing?
Interro-negative form
Simple form
could I not hail? could you not hail? could he not hail? could we not hail? could you not hail? could they not hail?
V-ing form
could I not be hailing? could you not be hailing? could he not be hailing? could we not be hailing? could you not be hailing? could they not be hailing?
Perfect
could I not have hailed? could you not have hailed? could he not have hailed? could we not have hailed? could you not have hailed? could they not have hailed?
V-ing perfect
could I not have been hailing? could you not have been hailing? could he not have been hailing? could we not have been hailing? could you not have been hailing? could they not have been hailing?