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