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 couldn't die you couldn't die he couldn't die we couldn't die you couldn't die they couldn't die
V-ing form
I couldn't be dying you couldn't be dying he couldn't be dying we couldn't be dying you couldn't be dying they couldn't be dying
Perfect
I couldn't have died you couldn't have died he couldn't have died we couldn't have died you couldn't have died they couldn't have died
V-ing perfect
I couldn't have been dying you couldn't have been dying he couldn't have been dying we couldn't have been dying you couldn't have been dying they couldn't 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
couldn't I die? couldn't you die? couldn't he die? couldn't we die? couldn't you die? couldn't they die?
V-ing form
couldn't I be dying? couldn't you be dying? couldn't he be dying? couldn't we be dying? couldn't you be dying? couldn't they be dying?
Perfect
couldn't I have died? couldn't you have died? couldn't he have died? couldn't we have died? couldn't you have died? couldn't they have died?
V-ing perfect
couldn't I have been dying? couldn't you have been dying? couldn't he have been dying? couldn't we have been dying? couldn't you have been dying? couldn't they have been dying?