I could disappear you could disappear he could disappear we could disappear you could disappear they could disappear
V-ing form
I could be disappearing you could be disappearing he could be disappearing we could be disappearing you could be disappearing they could be disappearing
Perfect
I could have disappeared you could have disappeared he could have disappeared we could have disappeared you could have disappeared they could have disappeared
V-ing perfect
I could have been disappearing you could have been disappearing he could have been disappearing we could have been disappearing you could have been disappearing they could have been disappearing
Negation
Simple form
I could not disappear you could not disappear he could not disappear we could not disappear you could not disappear they could not disappear
V-ing form
I could not be disappearing you could not be disappearing he could not be disappearing we could not be disappearing you could not be disappearing they could not be disappearing
Perfect
I could not have disappeared you could not have disappeared he could not have disappeared we could not have disappeared you could not have disappeared they could not have disappeared
V-ing perfect
I could not have been disappearing you could not have been disappearing he could not have been disappearing we could not have been disappearing you could not have been disappearing they could not have been disappearing
Interrogative form
Simple form
could I disappear? could you disappear? could he disappear? could we disappear? could you disappear? could they disappear?
V-ing form
could I be disappearing? could you be disappearing? could he be disappearing? could we be disappearing? could you be disappearing? could they be disappearing?
Perfect
could I have disappeared? could you have disappeared? could he have disappeared? could we have disappeared? could you have disappeared? could they have disappeared?
V-ing perfect
could I have been disappearing? could you have been disappearing? could he have been disappearing? could we have been disappearing? could you have been disappearing? could they have been disappearing?
Interro-negative form
Simple form
could I not disappear? could you not disappear? could he not disappear? could we not disappear? could you not disappear? could they not disappear?
V-ing form
could I not be disappearing? could you not be disappearing? could he not be disappearing? could we not be disappearing? could you not be disappearing? could they not be disappearing?
Perfect
could I not have disappeared? could you not have disappeared? could he not have disappeared? could we not have disappeared? could you not have disappeared? could they not have disappeared?
V-ing perfect
could I not have been disappearing? could you not have been disappearing? could he not have been disappearing? could we not have been disappearing? could you not have been disappearing? could they not have been disappearing?