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