线圈中感应电动势的方向,总是企图使它所产生的感应电流阻止原有的磁通变化
参考答案:对
— Mum, I really think Dad should have a break and get relaxed.
— Yes. He _______ too long.
A.read
B.has been reading
C.had read
D.is reading
发生对外现金业务,均应遵循“现金收款业务,先记账后收款;现金付款业务,先记账后付款”的原则。