When preparing a single injection for a patient who takes regular and neutral protein Hagedorn insulin, the nurse should draw the regular insulin into the syringe first so that it does not contaminate the regular insulin.

当为服用常规和低精蛋白锌胰岛素（NPH）的患者准备单次注射时，护士应首先将常规胰岛素吸入注射器，以免污染常规胰岛素。