must unbuild
Irregular verb: unbuild - unbuilt- unbuilt

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must unbuild
you must unbuild
he must unbuild
we must unbuild
you must unbuild
they must unbuild 	I must be unbuilding
you must be unbuilding
he must be unbuilding
we must be unbuilding
you must be unbuilding
they must be unbuilding	I must have unbuilt
you must have unbuilt
he must have unbuilt
we must have unbuilt
you must have unbuilt
they must have unbuilt	I must have been unbuilding
you must have been unbuilding
he must have been unbuilding
we must have been unbuilding
you must have been unbuilding
they must have been unbuilding	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't unbuild
you mustn't unbuild
he mustn't unbuild
we mustn't unbuild
you mustn't unbuild
they mustn't unbuild 	I mustn't be unbuilding
you mustn't be unbuilding
he mustn't be unbuilding
we mustn't be unbuilding
you mustn't be unbuilding
they mustn't be unbuilding	I mustn't have unbuilt
you mustn't have unbuilt
he mustn't have unbuilt
we mustn't have unbuilt
you mustn't have unbuilt
they mustn't have unbuilt	I mustn't have been unbuilding
you mustn't have been unbuilding
he mustn't have been unbuilding
we mustn't have been unbuilding
you mustn't have been unbuilding
they mustn't have been unbuilding	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I unbuild?
must you unbuild?
must he unbuild?
must we unbuild?
must you unbuild?
must they unbuild? 	must I be unbuilding?
must you be unbuilding?
must he be unbuilding?
must we be unbuilding?
must you be unbuilding?
must they be unbuilding? 	must I have unbuilt?
must you have unbuilt?
must he have unbuilt?
must we have unbuilt?
must you have unbuilt?
must they have unbuilt? 	must I have been unbuilding?
must you have been unbuilding?
must he have been unbuilding?
must we have been unbuilding?
must you have been unbuilding?
must they have been unbuilding? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I unbuild?
mustn't you unbuild?
mustn't he unbuild?
mustn't we unbuild?
mustn't you unbuild?
mustn't they unbuild? 	mustn't I be unbuilding?
mustn't you be unbuilding?
mustn't he be unbuilding?
mustn't we be unbuilding?
mustn't you be unbuilding?
mustn't they be unbuilding? 	mustn't I have unbuilt?
mustn't you have unbuilt?
mustn't he have unbuilt?
mustn't we have unbuilt?
mustn't you have unbuilt?
mustn't they have unbuilt? 	mustn't I have been unbuilding?
mustn't you have been unbuilding?
mustn't he have been unbuilding?
mustn't we have been unbuilding?
mustn't you have been unbuilding?
mustn't they have been unbuilding?