题目

质子交换膜燃料电池(PEMFC)常作为电动汽车的动力源。该燃料电池以氢气为燃料,空气为氧化剂,铂作催化剂,导电离子是H+。下列对该燃料电池的描述中正确的是( ) ①正极反应为O2+4H++4e-2H2O ②负极反应为2H2-4e-4H+ ③总的化学反应为2H2+O22H2O ④氢离子通过电解质向正极移动 A.①②③ B.②③④ C.①②④ D.①②③④Eating too much food that is high in fat and sugar, you'll ________ weight easily. [　　] A．put on B．put up C．put in D．put down