I may fasten you may fasten he may fasten we may fasten you may fasten they may fasten
V-ing form
I may be fastening you may be fastening he may be fastening we may be fastening you may be fastening they may be fastening
Perfect
I may have fastened you may have fastened he may have fastened we may have fastened you may have fastened they may have fastened
V-ing perfect
I may have been fastening you may have been fastening he may have been fastening we may have been fastening you may have been fastening they may have been fastening
Negation
Simple form
I mayn't fasten you mayn't fasten he mayn't fasten we mayn't fasten you mayn't fasten they mayn't fasten
V-ing form
I mayn't be fastening you mayn't be fastening he mayn't be fastening we mayn't be fastening you mayn't be fastening they mayn't be fastening
Perfect
I mayn't have fastened you mayn't have fastened he mayn't have fastened we mayn't have fastened you mayn't have fastened they mayn't have fastened
V-ing perfect
I mayn't have been fastening you mayn't have been fastening he mayn't have been fastening we mayn't have been fastening you mayn't have been fastening they mayn't have been fastening
Interrogative form
Simple form
may I fasten? may you fasten? may he fasten? may we fasten? may you fasten? may they fasten?
V-ing form
may I be fastening? may you be fastening? may he be fastening? may we be fastening? may you be fastening? may they be fastening?
Perfect
may I have fastened? may you have fastened? may he have fastened? may we have fastened? may you have fastened? may they have fastened?
V-ing perfect
may I have been fastening? may you have been fastening? may he have been fastening? may we have been fastening? may you have been fastening? may they have been fastening?
Interro-negative form
Simple form
mayn't I fasten? mayn't you fasten? mayn't he fasten? mayn't we fasten? mayn't you fasten? mayn't they fasten?
V-ing form
mayn't I be fastening? mayn't you be fastening? mayn't he be fastening? mayn't we be fastening? mayn't you be fastening? mayn't they be fastening?
Perfect
mayn't I have fastened? mayn't you have fastened? mayn't he have fastened? mayn't we have fastened? mayn't you have fastened? mayn't they have fastened?
V-ing perfect
mayn't I have been fastening? mayn't you have been fastening? mayn't he have been fastening? mayn't we have been fastening? mayn't you have been fastening? mayn't they have been fastening?