I must book you must book he must book we must book you must book they must book
V-ing form
I must be booking you must be booking he must be booking we must be booking you must be booking they must be booking
Perfect
I must have booked you must have booked he must have booked we must have booked you must have booked they must have booked
V-ing perfect
I must have been booking you must have been booking he must have been booking we must have been booking you must have been booking they must have been booking
Negation
Simple form
I must not book you must not book he must not book we must not book you must not book they must not book
V-ing form
I must not be booking you must not be booking he must not be booking we must not be booking you must not be booking they must not be booking
Perfect
I must not have booked you must not have booked he must not have booked we must not have booked you must not have booked they must not have booked
V-ing perfect
I must not have been booking you must not have been booking he must not have been booking we must not have been booking you must not have been booking they must not have been booking
Interrogative form
Simple form
must I book? must you book? must he book? must we book? must you book? must they book?
V-ing form
must I be booking? must you be booking? must he be booking? must we be booking? must you be booking? must they be booking?
Perfect
must I have booked? must you have booked? must he have booked? must we have booked? must you have booked? must they have booked?
V-ing perfect
must I have been booking? must you have been booking? must he have been booking? must we have been booking? must you have been booking? must they have been booking?
Interro-negative form
Simple form
must I not book? must you not book? must he not book? must we not book? must you not book? must they not book?
V-ing form
must I not be booking? must you not be booking? must he not be booking? must we not be booking? must you not be booking? must they not be booking?
Perfect
must I not have booked? must you not have booked? must he not have booked? must we not have booked? must you not have booked? must they not have booked?
V-ing perfect
must I not have been booking? must you not have been booking? must he not have been booking? must we not have been booking? must you not have been booking? must they not have been booking?