must labor
Regular verb: labor - labored- labored

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must labor
you must labor
he must labor
we must labor
you must labor
they must labor 	I must be laboring
you must be laboring
he must be laboring
we must be laboring
you must be laboring
they must be laboring	I must have labored
you must have labored
he must have labored
we must have labored
you must have labored
they must have labored	I must have been laboring
you must have been laboring
he must have been laboring
we must have been laboring
you must have been laboring
they must have been laboring	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't labor
you mustn't labor
he mustn't labor
we mustn't labor
you mustn't labor
they mustn't labor 	I mustn't be laboring
you mustn't be laboring
he mustn't be laboring
we mustn't be laboring
you mustn't be laboring
they mustn't be laboring	I mustn't have labored
you mustn't have labored
he mustn't have labored
we mustn't have labored
you mustn't have labored
they mustn't have labored	I mustn't have been laboring
you mustn't have been laboring
he mustn't have been laboring
we mustn't have been laboring
you mustn't have been laboring
they mustn't have been laboring	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I labor?
must you labor?
must he labor?
must we labor?
must you labor?
must they labor? 	must I be laboring?
must you be laboring?
must he be laboring?
must we be laboring?
must you be laboring?
must they be laboring? 	must I have labored?
must you have labored?
must he have labored?
must we have labored?
must you have labored?
must they have labored? 	must I have been laboring?
must you have been laboring?
must he have been laboring?
must we have been laboring?
must you have been laboring?
must they have been laboring? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I labor?
mustn't you labor?
mustn't he labor?
mustn't we labor?
mustn't you labor?
mustn't they labor? 	mustn't I be laboring?
mustn't you be laboring?
mustn't he be laboring?
mustn't we be laboring?
mustn't you be laboring?
mustn't they be laboring? 	mustn't I have labored?
mustn't you have labored?
mustn't he have labored?
mustn't we have labored?
mustn't you have labored?
mustn't they have labored? 	mustn't I have been laboring?
mustn't you have been laboring?
mustn't he have been laboring?
mustn't we have been laboring?
mustn't you have been laboring?
mustn't they have been laboring?