维生素C（C₆H₁₂O₆）主要存在于蔬菜、水果中。它能增强人体对疾病的抵抗能力。

阅读下面这首诗，完成小题。
                                                                                                        春游湖
                                                                                                     【宋】 徐俯
                                                                                       双飞燕子几时回？夹岸桃花蘸①水开。
                                                                                       春雨断桥人不度，小舟撑出绿阴来。
      【注释】①蘸：沾着水面。