I may stem you may stem she may stem we may stem you may stem they may stem
V-ing form
I may be stemming you may be stemming she may be stemming we may be stemming you may be stemming they may be stemming
Perfect
I may have stemmed you may have stemmed she may have stemmed we may have stemmed you may have stemmed they may have stemmed
V-ing perfect
I may have been stemming you may have been stemming she may have been stemming we may have been stemming you may have been stemming they may have been stemming
Negation
Simple form
I mayn't stem you mayn't stem she mayn't stem we mayn't stem you mayn't stem they mayn't stem
V-ing form
I mayn't be stemming you mayn't be stemming she mayn't be stemming we mayn't be stemming you mayn't be stemming they mayn't be stemming
Perfect
I mayn't have stemmed you mayn't have stemmed she mayn't have stemmed we mayn't have stemmed you mayn't have stemmed they mayn't have stemmed
V-ing perfect
I mayn't have been stemming you mayn't have been stemming she mayn't have been stemming we mayn't have been stemming you mayn't have been stemming they mayn't have been stemming
Interrogative form
Simple form
may I stem? may you stem? may she stem? may we stem? may you stem? may they stem?
V-ing form
may I be stemming? may you be stemming? may she be stemming? may we be stemming? may you be stemming? may they be stemming?
Perfect
may I have stemmed? may you have stemmed? may she have stemmed? may we have stemmed? may you have stemmed? may they have stemmed?
V-ing perfect
may I have been stemming? may you have been stemming? may she have been stemming? may we have been stemming? may you have been stemming? may they have been stemming?
Interro-negative form
Simple form
mayn't I stem? mayn't you stem? mayn't she stem? mayn't we stem? mayn't you stem? mayn't they stem?
V-ing form
mayn't I be stemming? mayn't you be stemming? mayn't she be stemming? mayn't we be stemming? mayn't you be stemming? mayn't they be stemming?
Perfect
mayn't I have stemmed? mayn't you have stemmed? mayn't she have stemmed? mayn't we have stemmed? mayn't you have stemmed? mayn't they have stemmed?
V-ing perfect
mayn't I have been stemming? mayn't you have been stemming? mayn't she have been stemming? mayn't we have been stemming? mayn't you have been stemming? mayn't they have been stemming?