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