I could crook you could crook she could crook we could crook you could crook they could crook
V-ing form
I could be crooking you could be crooking she could be crooking we could be crooking you could be crooking they could be crooking
Perfect
I could have crooked you could have crooked she 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 she 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 she 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 she 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 she 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 she 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 she crook? could we crook? could you crook? could they crook?
V-ing form
could I be crooking? could you be crooking? could she be crooking? could we be crooking? could you be crooking? could they be crooking?
Perfect
could I have crooked? could you have crooked? could she 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 she 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 she 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 she 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 she 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 she have been crooking? couldn't we have been crooking? couldn't you have been crooking? couldn't they have been crooking?