may stem
Regular verb: stem - stemmed- stemmed

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

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I may not stem
you may not stem
he may not stem
we may not stem
you may not stem
they may not stem 	I may not be stemming
you may not be stemming
he may not be stemming
we may not be stemming
you may not be stemming
they may not be stemming	I may not have stemmed
you may not have stemmed
he may not have stemmed
we may not have stemmed
you may not have stemmed
they may not have stemmed	I may not have been stemming
you may not have been stemming
he may not have been stemming
we may not have been stemming
you may not have been stemming
they may not have been stemming	

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

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
may I not stem?
may you not stem?
may he not stem?
may we not stem?
may you not stem?
may they not stem? 	may I not be stemming?
may you not be stemming?
may he not be stemming?
may we not be stemming?
may you not be stemming?
may they not be stemming? 	may I not have stemmed?
may you not have stemmed?
may he not have stemmed?
may we not have stemmed?
may you not have stemmed?
may they not have stemmed? 	may I not have been stemming?
may you not have been stemming?
may he not have been stemming?
may we not have been stemming?
may you not have been stemming?
may they not have been stemming?