I could swear you could swear he could swear we could swear you could swear they could swear
V-ing form
I could be swearing you could be swearing he could be swearing we could be swearing you could be swearing they could be swearing
Perfect
I could have sworn you could have sworn he could have sworn we could have sworn you could have sworn they could have sworn
V-ing perfect
I could have been swearing you could have been swearing he could have been swearing we could have been swearing you could have been swearing they could have been swearing
Negation
Simple form
I could not swear you could not swear he could not swear we could not swear you could not swear they could not swear
V-ing form
I could not be swearing you could not be swearing he could not be swearing we could not be swearing you could not be swearing they could not be swearing
Perfect
I could not have sworn you could not have sworn he could not have sworn we could not have sworn you could not have sworn they could not have sworn
V-ing perfect
I could not have been swearing you could not have been swearing he could not have been swearing we could not have been swearing you could not have been swearing they could not have been swearing
Interrogative form
Simple form
could I swear? could you swear? could he swear? could we swear? could you swear? could they swear?
V-ing form
could I be swearing? could you be swearing? could he be swearing? could we be swearing? could you be swearing? could they be swearing?
Perfect
could I have sworn? could you have sworn? could he have sworn? could we have sworn? could you have sworn? could they have sworn?
V-ing perfect
could I have been swearing? could you have been swearing? could he have been swearing? could we have been swearing? could you have been swearing? could they have been swearing?
Interro-negative form
Simple form
could I not swear? could you not swear? could he not swear? could we not swear? could you not swear? could they not swear?
V-ing form
could I not be swearing? could you not be swearing? could he not be swearing? could we not be swearing? could you not be swearing? could they not be swearing?
Perfect
could I not have sworn? could you not have sworn? could he not have sworn? could we not have sworn? could you not have sworn? could they not have sworn?
V-ing perfect
could I not have been swearing? could you not have been swearing? could he not have been swearing? could we not have been swearing? could you not have been swearing? could they not have been swearing?