must author
Regular verb: author - authored- authored

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must author
you must author
he must author
we must author
you must author
they must author 	I must be authoring
you must be authoring
he must be authoring
we must be authoring
you must be authoring
they must be authoring	I must have authored
you must have authored
he must have authored
we must have authored
you must have authored
they must have authored	I must have been authoring
you must have been authoring
he must have been authoring
we must have been authoring
you must have been authoring
they must have been authoring	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't author
you mustn't author
he mustn't author
we mustn't author
you mustn't author
they mustn't author 	I mustn't be authoring
you mustn't be authoring
he mustn't be authoring
we mustn't be authoring
you mustn't be authoring
they mustn't be authoring	I mustn't have authored
you mustn't have authored
he mustn't have authored
we mustn't have authored
you mustn't have authored
they mustn't have authored	I mustn't have been authoring
you mustn't have been authoring
he mustn't have been authoring
we mustn't have been authoring
you mustn't have been authoring
they mustn't have been authoring	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I author?
must you author?
must he author?
must we author?
must you author?
must they author? 	must I be authoring?
must you be authoring?
must he be authoring?
must we be authoring?
must you be authoring?
must they be authoring? 	must I have authored?
must you have authored?
must he have authored?
must we have authored?
must you have authored?
must they have authored? 	must I have been authoring?
must you have been authoring?
must he have been authoring?
must we have been authoring?
must you have been authoring?
must they have been authoring? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I author?
mustn't you author?
mustn't he author?
mustn't we author?
mustn't you author?
mustn't they author? 	mustn't I be authoring?
mustn't you be authoring?
mustn't he be authoring?
mustn't we be authoring?
mustn't you be authoring?
mustn't they be authoring? 	mustn't I have authored?
mustn't you have authored?
mustn't he have authored?
mustn't we have authored?
mustn't you have authored?
mustn't they have authored? 	mustn't I have been authoring?
mustn't you have been authoring?
mustn't he have been authoring?
mustn't we have been authoring?
mustn't you have been authoring?
mustn't they have been authoring?