题目

“You must give something back to your community,” my mother told me summers ago. Since she was  1   me to do something. I figured that I might as well enjoy it and so I decided to  2  swim lessons . I love the  3  and I thought I could  4  that love with others by helping little kids learn to swim. As an assistant to an instructor I started off . When I got in the water, I   5  a boy of about eight sitting on the edge of the poo1 looking   6 . That was how I got to know Jack. While   7  to get Jack in , I was told that he had a(n)  8  that caused him to be afraid of ma在LC振荡电路中，当振荡电流为零时，下列说法正确的是(    ) A.充电完毕                                               B.电场能开始向磁场能转化C.穿过线圈的磁通量变化率最小                    D.线圈中产生的自感电动势最小