may yack
Regular verb: yack - yacked- yacked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I may yack
you may yack
he may yack
we may yack
you may yack
they may yack 	I may be yacking
you may be yacking
he may be yacking
we may be yacking
you may be yacking
they may be yacking	I may have yacked
you may have yacked
he may have yacked
we may have yacked
you may have yacked
they may have yacked	I may have been yacking
you may have been yacking
he may have been yacking
we may have been yacking
you may have been yacking
they may have been yacking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mayn't yack
you mayn't yack
he mayn't yack
we mayn't yack
you mayn't yack
they mayn't yack 	I mayn't be yacking
you mayn't be yacking
he mayn't be yacking
we mayn't be yacking
you mayn't be yacking
they mayn't be yacking	I mayn't have yacked
you mayn't have yacked
he mayn't have yacked
we mayn't have yacked
you mayn't have yacked
they mayn't have yacked	I mayn't have been yacking
you mayn't have been yacking
he mayn't have been yacking
we mayn't have been yacking
you mayn't have been yacking
they mayn't have been yacking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
may I yack?
may you yack?
may he yack?
may we yack?
may you yack?
may they yack? 	may I be yacking?
may you be yacking?
may he be yacking?
may we be yacking?
may you be yacking?
may they be yacking? 	may I have yacked?
may you have yacked?
may he have yacked?
may we have yacked?
may you have yacked?
may they have yacked? 	may I have been yacking?
may you have been yacking?
may he have been yacking?
may we have been yacking?
may you have been yacking?
may they have been yacking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mayn't I yack?
mayn't you yack?
mayn't he yack?
mayn't we yack?
mayn't you yack?
mayn't they yack? 	mayn't I be yacking?
mayn't you be yacking?
mayn't he be yacking?
mayn't we be yacking?
mayn't you be yacking?
mayn't they be yacking? 	mayn't I have yacked?
mayn't you have yacked?
mayn't he have yacked?
mayn't we have yacked?
mayn't you have yacked?
mayn't they have yacked? 	mayn't I have been yacking?
mayn't you have been yacking?
mayn't he have been yacking?
mayn't we have been yacking?
mayn't you have been yacking?
mayn't they have been yacking?