may lack
Regular verb: lack - lacked- lacked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I may lack
you may lack
he may lack
we may lack
you may lack
they may lack 	I may be lacking
you may be lacking
he may be lacking
we may be lacking
you may be lacking
they may be lacking	I may have lacked
you may have lacked
he may have lacked
we may have lacked
you may have lacked
they may have lacked	I may have been lacking
you may have been lacking
he may have been lacking
we may have been lacking
you may have been lacking
they may have been lacking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mayn't lack
you mayn't lack
he mayn't lack
we mayn't lack
you mayn't lack
they mayn't lack 	I mayn't be lacking
you mayn't be lacking
he mayn't be lacking
we mayn't be lacking
you mayn't be lacking
they mayn't be lacking	I mayn't have lacked
you mayn't have lacked
he mayn't have lacked
we mayn't have lacked
you mayn't have lacked
they mayn't have lacked	I mayn't have been lacking
you mayn't have been lacking
he mayn't have been lacking
we mayn't have been lacking
you mayn't have been lacking
they mayn't have been lacking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
may I lack?
may you lack?
may he lack?
may we lack?
may you lack?
may they lack? 	may I be lacking?
may you be lacking?
may he be lacking?
may we be lacking?
may you be lacking?
may they be lacking? 	may I have lacked?
may you have lacked?
may he have lacked?
may we have lacked?
may you have lacked?
may they have lacked? 	may I have been lacking?
may you have been lacking?
may he have been lacking?
may we have been lacking?
may you have been lacking?
may they have been lacking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mayn't I lack?
mayn't you lack?
mayn't he lack?
mayn't we lack?
mayn't you lack?
mayn't they lack? 	mayn't I be lacking?
mayn't you be lacking?
mayn't he be lacking?
mayn't we be lacking?
mayn't you be lacking?
mayn't they be lacking? 	mayn't I have lacked?
mayn't you have lacked?
mayn't he have lacked?
mayn't we have lacked?
mayn't you have lacked?
mayn't they have lacked? 	mayn't I have been lacking?
mayn't you have been lacking?
mayn't he have been lacking?
mayn't we have been lacking?
mayn't you have been lacking?
mayn't they have been lacking?