I could unhook you could unhook he could unhook we could unhook you could unhook they could unhook
V-ing form
I could be unhooking you could be unhooking he could be unhooking we could be unhooking you could be unhooking they could be unhooking
Perfect
I could have unhooked you could have unhooked he could have unhooked we could have unhooked you could have unhooked they could have unhooked
V-ing perfect
I could have been unhooking you could have been unhooking he could have been unhooking we could have been unhooking you could have been unhooking they could have been unhooking
Negation
Simple form
I could not unhook you could not unhook he could not unhook we could not unhook you could not unhook they could not unhook
V-ing form
I could not be unhooking you could not be unhooking he could not be unhooking we could not be unhooking you could not be unhooking they could not be unhooking
Perfect
I could not have unhooked you could not have unhooked he could not have unhooked we could not have unhooked you could not have unhooked they could not have unhooked
V-ing perfect
I could not have been unhooking you could not have been unhooking he could not have been unhooking we could not have been unhooking you could not have been unhooking they could not have been unhooking
Interrogative form
Simple form
could I unhook? could you unhook? could he unhook? could we unhook? could you unhook? could they unhook?
V-ing form
could I be unhooking? could you be unhooking? could he be unhooking? could we be unhooking? could you be unhooking? could they be unhooking?
Perfect
could I have unhooked? could you have unhooked? could he have unhooked? could we have unhooked? could you have unhooked? could they have unhooked?
V-ing perfect
could I have been unhooking? could you have been unhooking? could he have been unhooking? could we have been unhooking? could you have been unhooking? could they have been unhooking?
Interro-negative form
Simple form
could I not unhook? could you not unhook? could he not unhook? could we not unhook? could you not unhook? could they not unhook?
V-ing form
could I not be unhooking? could you not be unhooking? could he not be unhooking? could we not be unhooking? could you not be unhooking? could they not be unhooking?
Perfect
could I not have unhooked? could you not have unhooked? could he not have unhooked? could we not have unhooked? could you not have unhooked? could they not have unhooked?
V-ing perfect
could I not have been unhooking? could you not have been unhooking? could he not have been unhooking? could we not have been unhooking? could you not have been unhooking? could they not have been unhooking?