题目

Never before in my life ________such a beautiful girl with so many high qualities.  A. I met    B. did I meet   C. I have met    D. have I met 答案：D 解析: 略现有反应：①CO+CuO  Cu+CO2     ②MgO+2HCl=MgCl2+H2O③Cu+2AgNO3=Cu（NO3）2+2Ag          ④CH4+2O2   CO2+2H2O⑤NH4HCO3NH3↑+CO2↑+H2O试回答：（1）上述属于置换反应的是______，属于复分解反应的是______．（2）属于氧化还原反应的是______．