In the publicity editor, some letter combinations such as Re, cos, log and ln will be recognized as keywords or function names and displayed in italics instead of variable names. If these letter combinations appear in the variable name you want to define, for example, the variable name is Reward, then Re will be displayed in the normal body and ward will be displayed in italics. At this point, select the reward and click the menu bar-> Style->; Variable, so the whole word Reward is displayed in italics.