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