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