题目

—She was nearly killed on the road. —Oh, when was that exactly? —It was in 2001        she was travelling with her friends. A. that                  B. when                C. while                D. why 答案：B19．在如图的电路中，R是已知阻值的电阻，根据已知条件和电表示数求出电阻Rx值的是（　　）A．B．C．D．