单项选择题
Collision rules（）apply to all vessels upon the high seas.
A.should B.must C.shall D.have to
单项选择题 Compared to manila line,size for size, nylon line（）.
单项选择题 Dry cargoes are those commodities that（）.
单项选择题 Each lifebuoy shall be marked in block capitals of the Roman alphabet with（）of the ship.
