must preoccupy
Regular verb: preoccupy - preoccupied- preoccupied

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must preoccupy
you must preoccupy
he must preoccupy
we must preoccupy
you must preoccupy
they must preoccupy 	I must be preoccupying
you must be preoccupying
he must be preoccupying
we must be preoccupying
you must be preoccupying
they must be preoccupying	I must have preoccupied
you must have preoccupied
he must have preoccupied
we must have preoccupied
you must have preoccupied
they must have preoccupied	I must have been preoccupying
you must have been preoccupying
he must have been preoccupying
we must have been preoccupying
you must have been preoccupying
they must have been preoccupying	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not preoccupy
you must not preoccupy
he must not preoccupy
we must not preoccupy
you must not preoccupy
they must not preoccupy 	I must not be preoccupying
you must not be preoccupying
he must not be preoccupying
we must not be preoccupying
you must not be preoccupying
they must not be preoccupying	I must not have preoccupied
you must not have preoccupied
he must not have preoccupied
we must not have preoccupied
you must not have preoccupied
they must not have preoccupied	I must not have been preoccupying
you must not have been preoccupying
he must not have been preoccupying
we must not have been preoccupying
you must not have been preoccupying
they must not have been preoccupying	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I preoccupy?
must you preoccupy?
must he preoccupy?
must we preoccupy?
must you preoccupy?
must they preoccupy? 	must I be preoccupying?
must you be preoccupying?
must he be preoccupying?
must we be preoccupying?
must you be preoccupying?
must they be preoccupying? 	must I have preoccupied?
must you have preoccupied?
must he have preoccupied?
must we have preoccupied?
must you have preoccupied?
must they have preoccupied? 	must I have been preoccupying?
must you have been preoccupying?
must he have been preoccupying?
must we have been preoccupying?
must you have been preoccupying?
must they have been preoccupying? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not preoccupy?
must you not preoccupy?
must he not preoccupy?
must we not preoccupy?
must you not preoccupy?
must they not preoccupy? 	must I not be preoccupying?
must you not be preoccupying?
must he not be preoccupying?
must we not be preoccupying?
must you not be preoccupying?
must they not be preoccupying? 	must I not have preoccupied?
must you not have preoccupied?
must he not have preoccupied?
must we not have preoccupied?
must you not have preoccupied?
must they not have preoccupied? 	must I not have been preoccupying?
must you not have been preoccupying?
must he not have been preoccupying?
must we not have been preoccupying?
must you not have been preoccupying?
must they not have been preoccupying?