题目

All countries need_________, timely and reliable climate information as well as high quality climate services , as they will benefit the whole humankind.        A. smart        B. accurate     C. particular   D. abstract 答案：B如图所示的振荡电路中，通过P点的电流如图所示，且通过P点的电流向右规定为i的正方向，则下列说法中正确的是 [　　] A．0.5s至1s时间内，电容器C在充电 B．0.5s至1s时间内，电容器C的上板带正电 C．1s至1.5s时间内，Q点比P点电势高 D．1s至1.5s时间内，磁场能正在转变成电场能