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