may strengthen
Regular verb: strengthen - strengthened- strengthened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I may strengthen
you may strengthen
she may strengthen
we may strengthen
you may strengthen
they may strengthen 	I may be strengthening
you may be strengthening
she may be strengthening
we may be strengthening
you may be strengthening
they may be strengthening	I may have strengthened
you may have strengthened
she may have strengthened
we may have strengthened
you may have strengthened
they may have strengthened	I may have been strengthening
you may have been strengthening
she may have been strengthening
we may have been strengthening
you may have been strengthening
they may have been strengthening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mayn't strengthen
you mayn't strengthen
she mayn't strengthen
we mayn't strengthen
you mayn't strengthen
they mayn't strengthen 	I mayn't be strengthening
you mayn't be strengthening
she mayn't be strengthening
we mayn't be strengthening
you mayn't be strengthening
they mayn't be strengthening	I mayn't have strengthened
you mayn't have strengthened
she mayn't have strengthened
we mayn't have strengthened
you mayn't have strengthened
they mayn't have strengthened	I mayn't have been strengthening
you mayn't have been strengthening
she mayn't have been strengthening
we mayn't have been strengthening
you mayn't have been strengthening
they mayn't have been strengthening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
may I strengthen?
may you strengthen?
may she strengthen?
may we strengthen?
may you strengthen?
may they strengthen? 	may I be strengthening?
may you be strengthening?
may she be strengthening?
may we be strengthening?
may you be strengthening?
may they be strengthening? 	may I have strengthened?
may you have strengthened?
may she have strengthened?
may we have strengthened?
may you have strengthened?
may they have strengthened? 	may I have been strengthening?
may you have been strengthening?
may she have been strengthening?
may we have been strengthening?
may you have been strengthening?
may they have been strengthening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mayn't I strengthen?
mayn't you strengthen?
mayn't she strengthen?
mayn't we strengthen?
mayn't you strengthen?
mayn't they strengthen? 	mayn't I be strengthening?
mayn't you be strengthening?
mayn't she be strengthening?
mayn't we be strengthening?
mayn't you be strengthening?
mayn't they be strengthening? 	mayn't I have strengthened?
mayn't you have strengthened?
mayn't she have strengthened?
mayn't we have strengthened?
mayn't you have strengthened?
mayn't they have strengthened? 	mayn't I have been strengthening?
mayn't you have been strengthening?
mayn't she have been strengthening?
mayn't we have been strengthening?
mayn't you have been strengthening?
mayn't they have been strengthening?