单项选择题
A red triangular daymark marks （）.
A.the centerline of a navigable channel B.the starboard side of a channel C.a prominent object of navigational interest that has no lateral significance D.an area of a channel where passing another vessel is permitted
单项选择题 A rapid rise or fall of the barometer indicates（）.
单项选择题 A radar range to a small，charted object such as a light will provide a line of position in which form? （）
单项选择题 A quick and rapid motion of a ship in a seaway is an indication of a(n) （）.
