雾天行驶，车速不能超过30公里/小时。（）
参考答案：对
It is very ______ that she will ring me tonight.[ ]
A. likely
B. possibly
C. probably
D. perhaps
A．变压器输出端所接电压表的示数为20V
B．变压器的输出功率为200W
C．变压器输出端的交流电的频率为50Hz
D．穿过变压器铁芯的磁通量变化率的最大值为20/n2Wb/s
V
/n2Wb/s