题目

M2O7X－与S2－ 在酸性溶液中发生如下反应：M2O7X－+3S2－+ZH+===YM3++3S↓+7H2O，则M2O7X－中M的化合价是（   ） A．+4        B．+5        C．+6       D．+7 答案：C－When could you have a meal with me? －I’d like to go wherever it is c_______ to you.