题目

_____ he got ready to leave home, his parents came to his home. A . While B . As C . Until D . If 答案：B金属M与AgNO3溶液反应的化学方程式为：M+2AgNO3=M（NO3）2+2Ag．则下列说法错误的是（　　） A．M的金属活动性比Ag强       B．金属M可能是铜 C．该反应属于复分解反应       D．该反应前后M的化合价发生了改变