may crack
Regular verb: crack - cracked- cracked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I may crack
you may crack
he may crack
we may crack
you may crack
they may crack 	I may be cracking
you may be cracking
he may be cracking
we may be cracking
you may be cracking
they may be cracking	I may have cracked
you may have cracked
he may have cracked
we may have cracked
you may have cracked
they may have cracked	I may have been cracking
you may have been cracking
he may have been cracking
we may have been cracking
you may have been cracking
they may have been cracking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mayn't crack
you mayn't crack
he mayn't crack
we mayn't crack
you mayn't crack
they mayn't crack 	I mayn't be cracking
you mayn't be cracking
he mayn't be cracking
we mayn't be cracking
you mayn't be cracking
they mayn't be cracking	I mayn't have cracked
you mayn't have cracked
he mayn't have cracked
we mayn't have cracked
you mayn't have cracked
they mayn't have cracked	I mayn't have been cracking
you mayn't have been cracking
he mayn't have been cracking
we mayn't have been cracking
you mayn't have been cracking
they mayn't have been cracking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
may I crack?
may you crack?
may he crack?
may we crack?
may you crack?
may they crack? 	may I be cracking?
may you be cracking?
may he be cracking?
may we be cracking?
may you be cracking?
may they be cracking? 	may I have cracked?
may you have cracked?
may he have cracked?
may we have cracked?
may you have cracked?
may they have cracked? 	may I have been cracking?
may you have been cracking?
may he have been cracking?
may we have been cracking?
may you have been cracking?
may they have been cracking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mayn't I crack?
mayn't you crack?
mayn't he crack?
mayn't we crack?
mayn't you crack?
mayn't they crack? 	mayn't I be cracking?
mayn't you be cracking?
mayn't he be cracking?
mayn't we be cracking?
mayn't you be cracking?
mayn't they be cracking? 	mayn't I have cracked?
mayn't you have cracked?
mayn't he have cracked?
mayn't we have cracked?
mayn't you have cracked?
mayn't they have cracked? 	mayn't I have been cracking?
mayn't you have been cracking?
mayn't he have been cracking?
mayn't we have been cracking?
mayn't you have been cracking?
mayn't they have been cracking?