题目

根据下列事实：①X＋Y2+＝X2+＋Y；②Z＋H2O（冷）＝Z(OH)2＋H2↑；③Z2+氧化性比X2+弱；④由Y、W电极组成的电池，电极反应为W2+＋2e-＝W、Y－2e-＝Y2+，可知X、Y、Z、W的还原性由强到弱的顺序为 ( ). A．X > Z > Y > W B．Z > W > X > Y C．Z > Y > X > W D．Z > X > Y > W 答案：D— Amy, I called you yesterday evening, but nobody answered the phone.— Oh, I _____ a walk with my mother at that time.A．take B．tookC．am taking D．was taking