单项选择题
Vessels in port may use（）for receiving typhoon warnings during the typhoon season.
A.their transmitters B.their receivers C.their radars D.their lorans
单项选择题 We’ll see（）the compasses are in good condition.
单项选择题 More exact assessment of visibility when（）is used to determine the range of vessel or other objects in the vicinity.
单项选择题 Which statement about satellite navigation is TRUE? （）
