突然短路事故
参考答案:
正常发电机电流是经负荷而构成闭路的,因某些原因,如金属物搭连、绝缘损坏、带地线误合闸等,使相与相或与地之间搭连,电流不经负荷构成闭路,这就叫突然短路事故
The teacher called Tom to his office because he was caught in the exam.
A.to cheat
B.cheating
C.cheated
D.cheat
对于任意的自然数n,(n+7)2﹣(n﹣5)2一定能被( )整除