题目

如图所示，铜棒ab沿垂直于磁场的方向向右加速运动，则（   ）       A．d端电势高于b端                              B．a端电势低于b端       C．ab间的电势差逐渐增大                      D．ab间的电势差逐渐减小  答案：AC解析: Everyone in the village hoped that he would _______ after a few days’ treatment. A. pick up          B. come up              C. keep up          D. make up