单项选择题
Vessels wishing to communicate with the Port Health Officer should do（）on VHF Channel 14.
A.so B.that C.this D.same
单项选择题 There is a VHF set（）the front of the wheelhouse.
单项选择题 There is a drifting mine（）in position 21 degrees 31 minutes North 124 degrees 20 minutes East.
单项选择题 There is a（）mine in position 50°N，30°W.
