单项选择题
When out of sight of land, a ship’s position can be found by using（）.
A.the coastal navigation B.the celestial navigation C.traditional navigation D.the great circle navigation
单项选择题 When visibility is reduced to about 5 miles, we say that visibility is（）.
单项选择题 When your vessel is proceeding to the area of traffic density,（）is used to determine the exact ranges of other ships or objects in the vicinity.
单项选择题 Which is wrong?（）.
