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