单项选择题
Your vessel has anchored in a channel known to have strong tidal currents. To check your position you take a round of bearings，one of which is a range in line. One hour later the bearing on the lights in range opens up. This indicates the ship is（）.
A.swinging B.dredging her anchor C.taking bearings of the lights D.taking distances of the lights
单项选择题 物资编码由（）位数字组成。
问答题 简述病症类型的粉、霉状物。
多项选择题 照明吊灯与地面垂直距离应符合（）等规定，否则应采用安全电压。
