单项选择题
The expression DROP ANCHOR means（）.
A.hold anchor B.leave anchor C.let go anchor D.weigh anchor
单项选择题 The best method to stop a vessel from dragging anchor in a sand bottom is to（）.
单项选择题 PAN-PAN repeated three times over the radiotelephone indicates which type of message will follow?（）
单项选择题 In radiotelephone communications，the prefix PAN-PAN indicates that（）.
