题目

若M2O7x－+3S2－+14H+=2M3++3S↓+7H2O，则M2O7x－中的M的化合价为 A.  +6          B．+4         C．+3        D．+2 答案：AChristmas is a holiday usually celebrated on December 25th _____ the birth of Jesus Christ. A. in charge of B. in terms of C. in favor of D. in honour of