English verb conjugation
MAY TOUGHEN

Regular verb: toughen - toughened - toughened

Affirmation

Simple form	V-ing form
I may toughen you may toughen he may toughen we may toughen you may toughen they may toughen	I may be toughening you may be toughening he may be toughening we may be toughening you may be toughening they may be toughening
Perfect	V-ing perfect
I may have toughened you may have toughened he may have toughened we may have toughened you may have toughened they may have toughened	I may have been toughening you may have been toughening he may have been toughening we may have been toughening you may have been toughening they may have been toughening

Negation

Simple form	V-ing form
I may not toughen you may not toughen he may not toughen we may not toughen you may not toughen they may not toughen	I may not be toughening you may not be toughening he may not be toughening we may not be toughening you may not be toughening they may not be toughening
Perfect	V-ing perfect
I may not have toughened you may not have toughened he may not have toughened we may not have toughened you may not have toughened they may not have toughened	I may not have been toughening you may not have been toughening he may not have been toughening we may not have been toughening you may not have been toughening they may not have been toughening

Interrogative form

Simple form	V-ing form
may I toughen? may you toughen? may he toughen? may we toughen? may you toughen? may they toughen?	may I be toughening? may you be toughening? may he be toughening? may we be toughening? may you be toughening? may they be toughening?
Perfect	V-ing perfect
may I have toughened? may you have toughened? may he have toughened? may we have toughened? may you have toughened? may they have toughened?	may I have been toughening? may you have been toughening? may he have been toughening? may we have been toughening? may you have been toughening? may they have been toughening?

Interro-negative form

Simple form	V-ing form
may I not toughen? may you not toughen? may he not toughen? may we not toughen? may you not toughen? may they not toughen?	may I not be toughening? may you not be toughening? may he not be toughening? may we not be toughening? may you not be toughening? may they not be toughening?
Perfect	V-ing perfect
may I not have toughened? may you not have toughened? may he not have toughened? may we not have toughened? may you not have toughened? may they not have toughened?	may I not have been toughening? may you not have been toughening? may he not have been toughening? may we not have been toughening? may you not have been toughening? may they not have been toughening?