I could fire you could fire he could fire we could fire you could fire they could fire
V-ing form
I could be firing you could be firing he could be firing we could be firing you could be firing they could be firing
Perfect
I could have fired you could have fired he could have fired we could have fired you could have fired they could have fired
V-ing perfect
I could have been firing you could have been firing he could have been firing we could have been firing you could have been firing they could have been firing
Negation
Simple form
I could not fire you could not fire he could not fire we could not fire you could not fire they could not fire
V-ing form
I could not be firing you could not be firing he could not be firing we could not be firing you could not be firing they could not be firing
Perfect
I could not have fired you could not have fired he could not have fired we could not have fired you could not have fired they could not have fired
V-ing perfect
I could not have been firing you could not have been firing he could not have been firing we could not have been firing you could not have been firing they could not have been firing
Interrogative form
Simple form
could I fire? could you fire? could he fire? could we fire? could you fire? could they fire?
V-ing form
could I be firing? could you be firing? could he be firing? could we be firing? could you be firing? could they be firing?
Perfect
could I have fired? could you have fired? could he have fired? could we have fired? could you have fired? could they have fired?
V-ing perfect
could I have been firing? could you have been firing? could he have been firing? could we have been firing? could you have been firing? could they have been firing?
Interro-negative form
Simple form
could I not fire? could you not fire? could he not fire? could we not fire? could you not fire? could they not fire?
V-ing form
could I not be firing? could you not be firing? could he not be firing? could we not be firing? could you not be firing? could they not be firing?
Perfect
could I not have fired? could you not have fired? could he not have fired? could we not have fired? could you not have fired? could they not have fired?
V-ing perfect
could I not have been firing? could you not have been firing? could he not have been firing? could we not have been firing? could you not have been firing? could they not have been firing?