don't I underestimate? don't you underestimate? doesn't she underestimate? don't we underestimate? don't you underestimate? don't they underestimate?
Present continuous
am I not underestimating? aren't you underestimating? isn't she underestimating? aren't we underestimating? aren't you underestimating? aren't they underestimating?
Preterite
didn't I underestimate? didn't you underestimate? didn't she underestimate? didn't we underestimate? didn't you underestimate? didn't they underestimate?
Preterite continuous
wasn't I underestimating? weren't you underestimating? wasn't she underestimating? weren't we underestimating? weren't you underestimating? weren't they underestimating?
Present perfect
haven't I underestimated? haven't you underestimated? hasn't she underestimated? haven't we underestimated? haven't you underestimated? haven't they underestimated?
Present perfect continuous
haven't I been underestimating? haven't you been underestimating? hasn't she been underestimating? haven't we been underestimating? haven't you been underestimating? haven't they been underestimating?
Pluperfect
hadn't I underestimated? hadn't you underestimated? hadn't she underestimated? hadn't we underestimated? hadn't you underestimated? hadn't they underestimated?
Pluperfect continuous
hadn't I been underestimating? hadn't you been underestimating? hadn't she been underestimating? hadn't we been underestimating? hadn't you been underestimating? hadn't they been underestimating?
Future
won't I underestimate? won't you underestimate? won't she underestimate? won't we underestimate? won't you underestimate? won't they underestimate?
Future continuous
won't I be underestimating? won't you be underestimating? won't she be underestimating? won't we be underestimating? won't you be underestimating? won't they be underestimating?
Future perfect
won't I have underestimated? won't you have underestimated? won't she have underestimated? won't we have underestimated? won't you have underestimated? won't they have underestimated?
Future perfect continuous
won't I have been underestimating? won't you have been underestimating? won't she have been underestimating? won't we have been underestimating? won't you have been underestimating? won't they have been underestimating?
Conditional
Present
wouldn't I underestimate? wouldn't you underestimate? wouldn't she underestimate? wouldn't we underestimate? wouldn't you underestimate? wouldn't they underestimate?
Present continuous
wouldn't I be underestimating? wouldn't you be underestimating? wouldn't she be underestimating? wouldn't we be underestimating? wouldn't you be underestimating? wouldn't they be underestimating?
Past
wouldn't I have underestimated? wouldn't you have underestimated? wouldn't she have underestimated? wouldn't we have underestimated? wouldn't you have underestimated? wouldn't they have underestimated?
Past continuous
wouldn't I have been underestimating? wouldn't you have been underestimating? wouldn't she have been underestimating? wouldn't we have been underestimating? wouldn't you have been underestimating? wouldn't they have been underestimating?