I could crook you could crook he could crook we could crook you could crook they could crook
V-ing form
I could be crooking you could be crooking he could be crooking we could be crooking you could be crooking they could be crooking
Perfect
I could have crooked you could have crooked he could have crooked we could have crooked you could have crooked they could have crooked
V-ing perfect
I could have been crooking you could have been crooking he could have been crooking we could have been crooking you could have been crooking they could have been crooking
Negation
Simple form
I couldn't crook you couldn't crook he couldn't crook we couldn't crook you couldn't crook they couldn't crook
V-ing form
I couldn't be crooking you couldn't be crooking he couldn't be crooking we couldn't be crooking you couldn't be crooking they couldn't be crooking
Perfect
I couldn't have crooked you couldn't have crooked he couldn't have crooked we couldn't have crooked you couldn't have crooked they couldn't have crooked
V-ing perfect
I couldn't have been crooking you couldn't have been crooking he couldn't have been crooking we couldn't have been crooking you couldn't have been crooking they couldn't have been crooking
Interrogative form
Simple form
could I crook? could you crook? could he crook? could we crook? could you crook? could they crook?
V-ing form
could I be crooking? could you be crooking? could he be crooking? could we be crooking? could you be crooking? could they be crooking?
Perfect
could I have crooked? could you have crooked? could he have crooked? could we have crooked? could you have crooked? could they have crooked?
V-ing perfect
could I have been crooking? could you have been crooking? could he have been crooking? could we have been crooking? could you have been crooking? could they have been crooking?
Interro-negative form
Simple form
couldn't I crook? couldn't you crook? couldn't he crook? couldn't we crook? couldn't you crook? couldn't they crook?
V-ing form
couldn't I be crooking? couldn't you be crooking? couldn't he be crooking? couldn't we be crooking? couldn't you be crooking? couldn't they be crooking?
Perfect
couldn't I have crooked? couldn't you have crooked? couldn't he have crooked? couldn't we have crooked? couldn't you have crooked? couldn't they have crooked?
V-ing perfect
couldn't I have been crooking? couldn't you have been crooking? couldn't he have been crooking? couldn't we have been crooking? couldn't you have been crooking? couldn't they have been crooking?