must comb
Regular verb: comb - combed- combed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must comb
you must comb
he must comb
we must comb
you must comb
they must comb 	I must be combing
you must be combing
he must be combing
we must be combing
you must be combing
they must be combing	I must have combed
you must have combed
he must have combed
we must have combed
you must have combed
they must have combed	I must have been combing
you must have been combing
he must have been combing
we must have been combing
you must have been combing
they must have been combing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't comb
you mustn't comb
he mustn't comb
we mustn't comb
you mustn't comb
they mustn't comb 	I mustn't be combing
you mustn't be combing
he mustn't be combing
we mustn't be combing
you mustn't be combing
they mustn't be combing	I mustn't have combed
you mustn't have combed
he mustn't have combed
we mustn't have combed
you mustn't have combed
they mustn't have combed	I mustn't have been combing
you mustn't have been combing
he mustn't have been combing
we mustn't have been combing
you mustn't have been combing
they mustn't have been combing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I comb?
must you comb?
must he comb?
must we comb?
must you comb?
must they comb? 	must I be combing?
must you be combing?
must he be combing?
must we be combing?
must you be combing?
must they be combing? 	must I have combed?
must you have combed?
must he have combed?
must we have combed?
must you have combed?
must they have combed? 	must I have been combing?
must you have been combing?
must he have been combing?
must we have been combing?
must you have been combing?
must they have been combing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I comb?
mustn't you comb?
mustn't he comb?
mustn't we comb?
mustn't you comb?
mustn't they comb? 	mustn't I be combing?
mustn't you be combing?
mustn't he be combing?
mustn't we be combing?
mustn't you be combing?
mustn't they be combing? 	mustn't I have combed?
mustn't you have combed?
mustn't he have combed?
mustn't we have combed?
mustn't you have combed?
mustn't they have combed? 	mustn't I have been combing?
mustn't you have been combing?
mustn't he have been combing?
mustn't we have been combing?
mustn't you have been combing?
mustn't they have been combing?