I must crook you must crook she must crook we must crook you must crook they must crook
V-ing form
I must be crooking you must be crooking she must be crooking we must be crooking you must be crooking they must be crooking
Perfect
I must have crooked you must have crooked she must have crooked we must have crooked you must have crooked they must have crooked
V-ing perfect
I must have been crooking you must have been crooking she must have been crooking we must have been crooking you must have been crooking they must have been crooking
Negation
Simple form
I must not crook you must not crook she must not crook we must not crook you must not crook they must not crook
V-ing form
I must not be crooking you must not be crooking she must not be crooking we must not be crooking you must not be crooking they must not be crooking
Perfect
I must not have crooked you must not have crooked she must not have crooked we must not have crooked you must not have crooked they must not have crooked
V-ing perfect
I must not have been crooking you must not have been crooking she must not have been crooking we must not have been crooking you must not have been crooking they must not have been crooking
Interrogative form
Simple form
must I crook? must you crook? must she crook? must we crook? must you crook? must they crook?
V-ing form
must I be crooking? must you be crooking? must she be crooking? must we be crooking? must you be crooking? must they be crooking?
Perfect
must I have crooked? must you have crooked? must she have crooked? must we have crooked? must you have crooked? must they have crooked?
V-ing perfect
must I have been crooking? must you have been crooking? must she have been crooking? must we have been crooking? must you have been crooking? must they have been crooking?
Interro-negative form
Simple form
must I not crook? must you not crook? must she not crook? must we not crook? must you not crook? must they not crook?
V-ing form
must I not be crooking? must you not be crooking? must she not be crooking? must we not be crooking? must you not be crooking? must they not be crooking?
Perfect
must I not have crooked? must you not have crooked? must she not have crooked? must we not have crooked? must you not have crooked? must they not have crooked?
V-ing perfect
must I not have been crooking? must you not have been crooking? must she not have been crooking? must we not have been crooking? must you not have been crooking? must they not have been crooking?