题目

Shenzhen Railway Line 8 to public since this October. A . has opened B . has been open C . had opened 答案：B甲、乙两用电器电功率之比为1∶2,通电时间之比为3∶4,则消耗电能之比为 ( )A. 1∶2 B. 3∶8 C. 3∶4 D. 2∶3