English verb conjugation
MUST STEM

Regular verb: stem - stemmed - stemmed

Affirmation

Simple form	V-ing form
I must stem you must stem he must stem we must stem you must stem they must stem	I must be stemming you must be stemming he must be stemming we must be stemming you must be stemming they must be stemming
Perfect	V-ing perfect
I must have stemmed you must have stemmed he must have stemmed we must have stemmed you must have stemmed they must have stemmed	I must have been stemming you must have been stemming he must have been stemming we must have been stemming you must have been stemming they must have been stemming

Negation

Simple form	V-ing form
I mustn't stem you mustn't stem he mustn't stem we mustn't stem you mustn't stem they mustn't stem	I mustn't be stemming you mustn't be stemming he mustn't be stemming we mustn't be stemming you mustn't be stemming they mustn't be stemming
Perfect	V-ing perfect
I mustn't have stemmed you mustn't have stemmed he mustn't have stemmed we mustn't have stemmed you mustn't have stemmed they mustn't have stemmed	I mustn't have been stemming you mustn't have been stemming he mustn't have been stemming we mustn't have been stemming you mustn't have been stemming they mustn't have been stemming

Interrogative form

Simple form	V-ing form
must I stem? must you stem? must he stem? must we stem? must you stem? must they stem?	must I be stemming? must you be stemming? must he be stemming? must we be stemming? must you be stemming? must they be stemming?
Perfect	V-ing perfect
must I have stemmed? must you have stemmed? must he have stemmed? must we have stemmed? must you have stemmed? must they have stemmed?	must I have been stemming? must you have been stemming? must he have been stemming? must we have been stemming? must you have been stemming? must they have been stemming?

Interro-negative form

Simple form	V-ing form
mustn't I stem? mustn't you stem? mustn't he stem? mustn't we stem? mustn't you stem? mustn't they stem?	mustn't I be stemming? mustn't you be stemming? mustn't he be stemming? mustn't we be stemming? mustn't you be stemming? mustn't they be stemming?
Perfect	V-ing perfect
mustn't I have stemmed? mustn't you have stemmed? mustn't he have stemmed? mustn't we have stemmed? mustn't you have stemmed? mustn't they have stemmed?	mustn't I have been stemming? mustn't you have been stemming? mustn't he have been stemming? mustn't we have been stemming? mustn't you have been stemming? mustn't they have been stemming?