题目

 通过一阻值R＝100 Ω的电阻的交变电流如图所示，其周期为1 s．电阻两端电压的有效值为________. 答案：12.64The woman ________ a baby ________ her arms scolded the young man ________ his manners.A.took; in; forB.taking; for; forC.took; on; toD.taking; in; for