【单选题】三相交流电:three-() alternating current
【单选题】每秒内正弦量变化的次数称为频率,用f表示,单位是什么。
【简答题】A.He suffered from heart faiinre and (tied. B.He won three awards alter his death. C.His plays were writ-ten based on his own life. D.He was a victim of the American system.
【单选题】“独学而无友,则孤陋而寡闻”, 是说大学学习,不仅要自己潜心苦学,也需要相互沟通、交流。这是讲的( )。