must subserve
Regular verb: subserve - subserved- subserved

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must subserve
you must subserve
she must subserve
we must subserve
you must subserve
they must subserve 	I must be subserving
you must be subserving
she must be subserving
we must be subserving
you must be subserving
they must be subserving	I must have subserved
you must have subserved
she must have subserved
we must have subserved
you must have subserved
they must have subserved	I must have been subserving
you must have been subserving
she must have been subserving
we must have been subserving
you must have been subserving
they must have been subserving	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't subserve
you mustn't subserve
she mustn't subserve
we mustn't subserve
you mustn't subserve
they mustn't subserve 	I mustn't be subserving
you mustn't be subserving
she mustn't be subserving
we mustn't be subserving
you mustn't be subserving
they mustn't be subserving	I mustn't have subserved
you mustn't have subserved
she mustn't have subserved
we mustn't have subserved
you mustn't have subserved
they mustn't have subserved	I mustn't have been subserving
you mustn't have been subserving
she mustn't have been subserving
we mustn't have been subserving
you mustn't have been subserving
they mustn't have been subserving	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I subserve?
must you subserve?
must she subserve?
must we subserve?
must you subserve?
must they subserve? 	must I be subserving?
must you be subserving?
must she be subserving?
must we be subserving?
must you be subserving?
must they be subserving? 	must I have subserved?
must you have subserved?
must she have subserved?
must we have subserved?
must you have subserved?
must they have subserved? 	must I have been subserving?
must you have been subserving?
must she have been subserving?
must we have been subserving?
must you have been subserving?
must they have been subserving? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I subserve?
mustn't you subserve?
mustn't she subserve?
mustn't we subserve?
mustn't you subserve?
mustn't they subserve? 	mustn't I be subserving?
mustn't you be subserving?
mustn't she be subserving?
mustn't we be subserving?
mustn't you be subserving?
mustn't they be subserving? 	mustn't I have subserved?
mustn't you have subserved?
mustn't she have subserved?
mustn't we have subserved?
mustn't you have subserved?
mustn't they have subserved? 	mustn't I have been subserving?
mustn't you have been subserving?
mustn't she have been subserving?
mustn't we have been subserving?
mustn't you have been subserving?
mustn't they have been subserving?