变电所的防雷保护有()线路传来的()及落雷时产生的()。
参考答案:直接雷击过电压;感应入侵波过电压;反击过电压
— The plane is due to take off at 7:50 from the airport. _____ we fail to arrive there in time?
— Try to take another flight then. [ ]
A. What if
B. As if
C. Even if
D. Only if
CAN线中,两根线之间的正常电压应为()
A.3.5V
B.5V
C.2.5-3.5V
D.1.5-2.5V