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