题目

A Story on an IslandA ship was lost at sea and the only survivor was washed up on a small, inhabited (无人居住的) island. He prayed __ for God to rescue him and for hours he just__at the horizon (地平线), waiting for a heaven-sent ___but it never came.Then he decided to do something. ___tired and upset, he ___some branches and dry grass. Hours of hard work paid off and a little shelter was built. The “Robinson Crusoe” began his life on the island. Believe it or not, a couple of days going by, he_____and it seemed not that hard.But then one day, after__ for food, he arrived home to 甲醇燃料电池由于结构简单、能量转化率高、对环境无污染，可作为常规能源的替代品而越来越受到关注，其工作示意图如下，其总反应为 2CH3OH＋3O2===2CO2＋4H2O。下列说法不正确的是( )A. 电极 A 是负极，物质 a 为甲醇B. 电池工作时，电解液中的 H＋通过质子交换膜向 B 电极迁移C. 放电前后电解质溶液的 pH 增大D. b 物质在电极上发生的电极反应式为： O2+4eˉ+2H2O＝4OHˉ