题目

Our government attaches great importance _____ the gap between the rich and poor.     A. to reduce   B. to reducing    C. of reducing    D. about reducing 答案：B将R1=10Ω、R2=20Ω的电阻串联接在正弦交流电路中，通过电阻R2的电流i随时间t变化的情况如图所示．则（　　）A、R1的消耗的电功率是3.6WB、R2两端的电压有效值是6VC、通过R2的电流有效值是0.6AD、R2两端的电压有效值是62V