单项选择题
A.AIS
B.SSAS
C.SSP
D.SART
单项选择题 Which of following physical abilities is not required as to the routine movement around a vessel?()
单项选择题 The information regarding ports such as buoyed channels,fairway,location and number of terminals,river channels,details of navigational marks,location of overhead bridges, underground cables etc. are shown in()
单项选择题 On a weather map,a large letter “h” means()