A. flashes at regular intervals of 50-70 flashes per minute B. is yellow in color C. shows an unbroken light over an arc of the horizon of not less than 180°nor more than 225° D. All of the above
A. 随机 B. 线性 C. 对数 D. 快开 E. 相性
A. 正常定单 B. 存储定单 C. 服务定单 D. 变更定单
A. 正确 B. 错误