I could coal you could coal he could coal we could coal you could coal they could coal
V-ing form
I could be coaling you could be coaling he could be coaling we could be coaling you could be coaling they could be coaling
Perfect
I could have coaled you could have coaled he could have coaled we could have coaled you could have coaled they could have coaled
V-ing perfect
I could have been coaling you could have been coaling he could have been coaling we could have been coaling you could have been coaling they could have been coaling
Negation
Simple form
I could not coal you could not coal he could not coal we could not coal you could not coal they could not coal
V-ing form
I could not be coaling you could not be coaling he could not be coaling we could not be coaling you could not be coaling they could not be coaling
Perfect
I could not have coaled you could not have coaled he could not have coaled we could not have coaled you could not have coaled they could not have coaled
V-ing perfect
I could not have been coaling you could not have been coaling he could not have been coaling we could not have been coaling you could not have been coaling they could not have been coaling
Interrogative form
Simple form
could I coal? could you coal? could he coal? could we coal? could you coal? could they coal?
V-ing form
could I be coaling? could you be coaling? could he be coaling? could we be coaling? could you be coaling? could they be coaling?
Perfect
could I have coaled? could you have coaled? could he have coaled? could we have coaled? could you have coaled? could they have coaled?
V-ing perfect
could I have been coaling? could you have been coaling? could he have been coaling? could we have been coaling? could you have been coaling? could they have been coaling?
Interro-negative form
Simple form
could I not coal? could you not coal? could he not coal? could we not coal? could you not coal? could they not coal?
V-ing form
could I not be coaling? could you not be coaling? could he not be coaling? could we not be coaling? could you not be coaling? could they not be coaling?
Perfect
could I not have coaled? could you not have coaled? could he not have coaled? could we not have coaled? could you not have coaled? could they not have coaled?
V-ing perfect
could I not have been coaling? could you not have been coaling? could he not have been coaling? could we not have been coaling? could you not have been coaling? could they not have been coaling?