I may knock you may knock he may knock we may knock you may knock they may knock
V-ing form
I may be knocking you may be knocking he may be knocking we may be knocking you may be knocking they may be knocking
Perfect
I may have knocked you may have knocked he may have knocked we may have knocked you may have knocked they may have knocked
V-ing perfect
I may have been knocking you may have been knocking he may have been knocking we may have been knocking you may have been knocking they may have been knocking
Negation
Simple form
I may not knock you may not knock he may not knock we may not knock you may not knock they may not knock
V-ing form
I may not be knocking you may not be knocking he may not be knocking we may not be knocking you may not be knocking they may not be knocking
Perfect
I may not have knocked you may not have knocked he may not have knocked we may not have knocked you may not have knocked they may not have knocked
V-ing perfect
I may not have been knocking you may not have been knocking he may not have been knocking we may not have been knocking you may not have been knocking they may not have been knocking
Interrogative form
Simple form
may I knock? may you knock? may he knock? may we knock? may you knock? may they knock?
V-ing form
may I be knocking? may you be knocking? may he be knocking? may we be knocking? may you be knocking? may they be knocking?
Perfect
may I have knocked? may you have knocked? may he have knocked? may we have knocked? may you have knocked? may they have knocked?
V-ing perfect
may I have been knocking? may you have been knocking? may he have been knocking? may we have been knocking? may you have been knocking? may they have been knocking?
Interro-negative form
Simple form
may I not knock? may you not knock? may he not knock? may we not knock? may you not knock? may they not knock?
V-ing form
may I not be knocking? may you not be knocking? may he not be knocking? may we not be knocking? may you not be knocking? may they not be knocking?
Perfect
may I not have knocked? may you not have knocked? may he not have knocked? may we not have knocked? may you not have knocked? may they not have knocked?
V-ing perfect
may I not have been knocking? may you not have been knocking? may he not have been knocking? may we not have been knocking? may you not have been knocking? may they not have been knocking?