I must preface you must preface he must preface we must preface you must preface they must preface
V-ing form
I must be prefacing you must be prefacing he must be prefacing we must be prefacing you must be prefacing they must be prefacing
Perfect
I must have prefaced you must have prefaced he must have prefaced we must have prefaced you must have prefaced they must have prefaced
V-ing perfect
I must have been prefacing you must have been prefacing he must have been prefacing we must have been prefacing you must have been prefacing they must have been prefacing
Negation
Simple form
I mustn't preface you mustn't preface he mustn't preface we mustn't preface you mustn't preface they mustn't preface
V-ing form
I mustn't be prefacing you mustn't be prefacing he mustn't be prefacing we mustn't be prefacing you mustn't be prefacing they mustn't be prefacing
Perfect
I mustn't have prefaced you mustn't have prefaced he mustn't have prefaced we mustn't have prefaced you mustn't have prefaced they mustn't have prefaced
V-ing perfect
I mustn't have been prefacing you mustn't have been prefacing he mustn't have been prefacing we mustn't have been prefacing you mustn't have been prefacing they mustn't have been prefacing
Interrogative form
Simple form
must I preface? must you preface? must he preface? must we preface? must you preface? must they preface?
V-ing form
must I be prefacing? must you be prefacing? must he be prefacing? must we be prefacing? must you be prefacing? must they be prefacing?
Perfect
must I have prefaced? must you have prefaced? must he have prefaced? must we have prefaced? must you have prefaced? must they have prefaced?
V-ing perfect
must I have been prefacing? must you have been prefacing? must he have been prefacing? must we have been prefacing? must you have been prefacing? must they have been prefacing?
Interro-negative form
Simple form
mustn't I preface? mustn't you preface? mustn't he preface? mustn't we preface? mustn't you preface? mustn't they preface?
V-ing form
mustn't I be prefacing? mustn't you be prefacing? mustn't he be prefacing? mustn't we be prefacing? mustn't you be prefacing? mustn't they be prefacing?
Perfect
mustn't I have prefaced? mustn't you have prefaced? mustn't he have prefaced? mustn't we have prefaced? mustn't you have prefaced? mustn't they have prefaced?
V-ing perfect
mustn't I have been prefacing? mustn't you have been prefacing? mustn't he have been prefacing? mustn't we have been prefacing? mustn't you have been prefacing? mustn't they have been prefacing?