must prefab
Regular verb: prefab - prefabed- prefabed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must prefab
you must prefab
he must prefab
we must prefab
you must prefab
they must prefab 	I must be prefabing
you must be prefabing
he must be prefabing
we must be prefabing
you must be prefabing
they must be prefabing	I must have prefabed
you must have prefabed
he must have prefabed
we must have prefabed
you must have prefabed
they must have prefabed	I must have been prefabing
you must have been prefabing
he must have been prefabing
we must have been prefabing
you must have been prefabing
they must have been prefabing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't prefab
you mustn't prefab
he mustn't prefab
we mustn't prefab
you mustn't prefab
they mustn't prefab 	I mustn't be prefabing
you mustn't be prefabing
he mustn't be prefabing
we mustn't be prefabing
you mustn't be prefabing
they mustn't be prefabing	I mustn't have prefabed
you mustn't have prefabed
he mustn't have prefabed
we mustn't have prefabed
you mustn't have prefabed
they mustn't have prefabed	I mustn't have been prefabing
you mustn't have been prefabing
he mustn't have been prefabing
we mustn't have been prefabing
you mustn't have been prefabing
they mustn't have been prefabing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I prefab?
must you prefab?
must he prefab?
must we prefab?
must you prefab?
must they prefab? 	must I be prefabing?
must you be prefabing?
must he be prefabing?
must we be prefabing?
must you be prefabing?
must they be prefabing? 	must I have prefabed?
must you have prefabed?
must he have prefabed?
must we have prefabed?
must you have prefabed?
must they have prefabed? 	must I have been prefabing?
must you have been prefabing?
must he have been prefabing?
must we have been prefabing?
must you have been prefabing?
must they have been prefabing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I prefab?
mustn't you prefab?
mustn't he prefab?
mustn't we prefab?
mustn't you prefab?
mustn't they prefab? 	mustn't I be prefabing?
mustn't you be prefabing?
mustn't he be prefabing?
mustn't we be prefabing?
mustn't you be prefabing?
mustn't they be prefabing? 	mustn't I have prefabed?
mustn't you have prefabed?
mustn't he have prefabed?
mustn't we have prefabed?
mustn't you have prefabed?
mustn't they have prefabed? 	mustn't I have been prefabing?
mustn't you have been prefabing?
mustn't he have been prefabing?
mustn't we have been prefabing?
mustn't you have been prefabing?
mustn't they have been prefabing?