Can an issue not raised before the trial court be raised for the first time on appeal?

Issues not raised before the trial court generally cannot be raised for the first time on appeal. United States v. Flores-Payon, 942 F.2d 556, 558 (9th Cir.1991). We have recognized three narrow exceptions to this general rule: (1) when there are "exceptional circumstances" as to why the issue was not raised in the trial court, (2) when the issue arises while appeal is pending because of a change in the law, or (3) when the issue is purely one of law, the pertinent record has been fully developed, and the opposing party will not be prejudiced by the failure to raise the issue below. Id. "Further exception may be made when plain error has occurred and an injustice might otherwise result." Id.