may refer
Verbo regular: refer - referred- referred

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I may refer
you may refer
he may refer
we may refer
you may refer
they may refer 	I may be referring
you may be referring
he may be referring
we may be referring
you may be referring
they may be referring	I may have referred
you may have referred
he may have referred
we may have referred
you may have referred
they may have referred	I may have been referring
you may have been referring
he may have been referring
we may have been referring
you may have been referring
they may have been referring	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I mayn't refer
you mayn't refer
he mayn't refer
we mayn't refer
you mayn't refer
they mayn't refer 	I mayn't be referring
you mayn't be referring
he mayn't be referring
we mayn't be referring
you mayn't be referring
they mayn't be referring	I mayn't have referred
you mayn't have referred
he mayn't have referred
we mayn't have referred
you mayn't have referred
they mayn't have referred	I mayn't have been referring
you mayn't have been referring
he mayn't have been referring
we mayn't have been referring
you mayn't have been referring
they mayn't have been referring	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
may I refer?
may you refer?
may he refer?
may we refer?
may you refer?
may they refer? 	may I be referring?
may you be referring?
may he be referring?
may we be referring?
may you be referring?
may they be referring? 	may I have referred?
may you have referred?
may he have referred?
may we have referred?
may you have referred?
may they have referred? 	may I have been referring?
may you have been referring?
may he have been referring?
may we have been referring?
may you have been referring?
may they have been referring? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
mayn't I refer?
mayn't you refer?
mayn't he refer?
mayn't we refer?
mayn't you refer?
mayn't they refer? 	mayn't I be referring?
mayn't you be referring?
mayn't he be referring?
mayn't we be referring?
mayn't you be referring?
mayn't they be referring? 	mayn't I have referred?
mayn't you have referred?
mayn't he have referred?
mayn't we have referred?
mayn't you have referred?
mayn't they have referred? 	mayn't I have been referring?
mayn't you have been referring?
mayn't he have been referring?
mayn't we have been referring?
mayn't you have been referring?
mayn't they have been referring?