A:an=(﹣1)n
B:an=(﹣1)n+1
C:an=(﹣1)n﹣1
D:an= {1,n为奇数-1,n为偶数 v
如图所示的电路中,有几根导线尚未连接,请用笔画线代替导线补上.补上后要求:
(1)两灯泡并联;
(2)电流表测灯L1的电流;
(3)闭合开关后,向A端移动滑动变阻器的滑片P,两灯均变暗.
Were you happy yesterday? Yes, ________.