【单选题】Current flowing in only one direction is called _____.
B.
omnidirectional current
【单选题】Current flowing in only one direction is called _____
【单选题】The current flowing first in one direction and then in another is called_____ current.
【单选题】使用含氯消毒液对手部进行消毒 , 应江双手在消毒液中浸泡至少 ( ) 。