题目

Steven has a lot of work to _______ in the office since he has been away for quite a few days. A. take up      B. make up     C. work out    D. carry out 答案：BX、Y、Z、M、N代表五种金属，有以下化学反应①水溶液中：X＋Y2+=X2+＋Y ②Z＋2H2O(冷水)=Z(OH)2＋H2↑③M、N 为电极，与N盐溶液组成原电池，M电极反应为：M－2e- =M2+④Y 可以溶于稀硫酸中，M 不被稀硫酸氧化。则这五种金属的活泼性由弱到强的顺序是 A．M＜N＜Y＜X＜Z B．N＜M＜X＜Y＜Z C．N＜M＜Y＜X＜Z D．X＜Z＜N＜M＜Y