单选题 ______________is a satellite system promulgating Maritime Safety Information

单选题 Via shipboard satellite-based systems，__________is available

单选题 In addition to the identification and position of the ship in distress， the distress alert may also contain informationRegarding the____________， the type of assistance， the course and speed of the ship and the time at which the informationWas recorded

单选题 The followings are all characteristics of portable VHF radiotelephone sets， except____

单选题 Operator at sea received a distress alert on the frequency of 156.525Mhz， he should keep listening watch on ____________,

单选题 A Navtex station in each NAVAREA is usually allowed to have_________for transmission.

单选题 ____________means safety communications between ships from the position from which the ships are normallyNavigated.

单选题 If a ship is fitted with a VHF radio installation， while at sea， shall______________,