I may caution you may caution he may caution we may caution you may caution they may caution
V-ing form
I may be cautioning you may be cautioning he may be cautioning we may be cautioning you may be cautioning they may be cautioning
Perfect
I may have cautioned you may have cautioned he may have cautioned we may have cautioned you may have cautioned they may have cautioned
V-ing perfect
I may have been cautioning you may have been cautioning he may have been cautioning we may have been cautioning you may have been cautioning they may have been cautioning
Negation
Simple form
I may not caution you may not caution he may not caution we may not caution you may not caution they may not caution
V-ing form
I may not be cautioning you may not be cautioning he may not be cautioning we may not be cautioning you may not be cautioning they may not be cautioning
Perfect
I may not have cautioned you may not have cautioned he may not have cautioned we may not have cautioned you may not have cautioned they may not have cautioned
V-ing perfect
I may not have been cautioning you may not have been cautioning he may not have been cautioning we may not have been cautioning you may not have been cautioning they may not have been cautioning
Interrogative form
Simple form
may I caution? may you caution? may he caution? may we caution? may you caution? may they caution?
V-ing form
may I be cautioning? may you be cautioning? may he be cautioning? may we be cautioning? may you be cautioning? may they be cautioning?
Perfect
may I have cautioned? may you have cautioned? may he have cautioned? may we have cautioned? may you have cautioned? may they have cautioned?
V-ing perfect
may I have been cautioning? may you have been cautioning? may he have been cautioning? may we have been cautioning? may you have been cautioning? may they have been cautioning?
Interro-negative form
Simple form
may I not caution? may you not caution? may he not caution? may we not caution? may you not caution? may they not caution?
V-ing form
may I not be cautioning? may you not be cautioning? may he not be cautioning? may we not be cautioning? may you not be cautioning? may they not be cautioning?
Perfect
may I not have cautioned? may you not have cautioned? may he not have cautioned? may we not have cautioned? may you not have cautioned? may they not have cautioned?
V-ing perfect
may I not have been cautioning? may you not have been cautioning? may he not have been cautioning? may we not have been cautioning? may you not have been cautioning? may they not have been cautioning?