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