题目

A．用户用电器上交流电的频率是 100 Hz B．发电机输出交流电的电压有效值是 500 V C．输电线的电流只由降压变压器原副线圈的匝数比决定 D．当用户用电器的总电阻增大时，输电线上损失的功率减小 答案：DHis jewelry shop is said ____ and he can't help but____ the fact. [     ]A. robbing; to accept            B. to rob; acceptsC. to have robbed; accept        D. to have been robbed; accept