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