交流电完成一次循环所需要的时间叫()。 A.频率 B.周期 C.速率 D.正弦曲线 发布时间:2018-01-22 18:21 │ 来源:www.tikuol.com 题型:单项选择题 问题: 交流电完成一次循环所需要的时间叫()。A.频率B.周期C.速率D.正弦曲线
题型:单项选择题 _______,I lost heart in English learning,but my teacher often said to me,"Keep on working hard; you'll succeed________."[ ]A. At a time; in time B. At a time; on timeC. At one time; in time D. At one time; on time 查看答案