I may knock you may knock she may knock we may knock you may knock they may knock
V-ing form
I may be knocking you may be knocking she may be knocking we may be knocking you may be knocking they may be knocking
Perfect
I may have knocked you may have knocked she 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 she may have been knocking we may have been knocking you may have been knocking they may have been knocking
Negation
Simple form
I mayn't knock you mayn't knock she mayn't knock we mayn't knock you mayn't knock they mayn't knock
V-ing form
I mayn't be knocking you mayn't be knocking she mayn't be knocking we mayn't be knocking you mayn't be knocking they mayn't be knocking
Perfect
I mayn't have knocked you mayn't have knocked she mayn't have knocked we mayn't have knocked you mayn't have knocked they mayn't have knocked
V-ing perfect
I mayn't have been knocking you mayn't have been knocking she mayn't have been knocking we mayn't have been knocking you mayn't have been knocking they mayn't have been knocking
Interrogative form
Simple form
may I knock? may you knock? may she knock? may we knock? may you knock? may they knock?
V-ing form
may I be knocking? may you be knocking? may she be knocking? may we be knocking? may you be knocking? may they be knocking?
Perfect
may I have knocked? may you have knocked? may she 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 she have been knocking? may we have been knocking? may you have been knocking? may they have been knocking?
Interro-negative form
Simple form
mayn't I knock? mayn't you knock? mayn't she knock? mayn't we knock? mayn't you knock? mayn't they knock?
V-ing form
mayn't I be knocking? mayn't you be knocking? mayn't she be knocking? mayn't we be knocking? mayn't you be knocking? mayn't they be knocking?
Perfect
mayn't I have knocked? mayn't you have knocked? mayn't she have knocked? mayn't we have knocked? mayn't you have knocked? mayn't they have knocked?
V-ing perfect
mayn't I have been knocking? mayn't you have been knocking? mayn't she have been knocking? mayn't we have been knocking? mayn't you have been knocking? mayn't they have been knocking?