I could die you could die he could die we could die you could die they could die
V-ing form
I could be dying you could be dying he could be dying we could be dying you could be dying they could be dying
Perfect
I could have died you could have died he could have died we could have died you could have died they could have died
V-ing perfect
I could have been dying you could have been dying he could have been dying we could have been dying you could have been dying they could have been dying
Negation
Simple form
I could not die you could not die he could not die we could not die you could not die they could not die
V-ing form
I could not be dying you could not be dying he could not be dying we could not be dying you could not be dying they could not be dying
Perfect
I could not have died you could not have died he could not have died we could not have died you could not have died they could not have died
V-ing perfect
I could not have been dying you could not have been dying he could not have been dying we could not have been dying you could not have been dying they could not have been dying
Interrogative form
Simple form
could I die? could you die? could he die? could we die? could you die? could they die?
V-ing form
could I be dying? could you be dying? could he be dying? could we be dying? could you be dying? could they be dying?
Perfect
could I have died? could you have died? could he have died? could we have died? could you have died? could they have died?
V-ing perfect
could I have been dying? could you have been dying? could he have been dying? could we have been dying? could you have been dying? could they have been dying?
Interro-negative form
Simple form
could I not die? could you not die? could he not die? could we not die? could you not die? could they not die?
V-ing form
could I not be dying? could you not be dying? could he not be dying? could we not be dying? could you not be dying? could they not be dying?
Perfect
could I not have died? could you not have died? could he not have died? could we not have died? could you not have died? could they not have died?
V-ing perfect
could I not have been dying? could you not have been dying? could he not have been dying? could we not have been dying? could you not have been dying? could they not have been dying?