单项选择题 When commencing cargo operations on a container ship，one cell at a hatch is generally discharged completely (to the bottom of the ship) before removing any containers from the adjoining cells to（）.

单项选择题 When clearing customs for a foreign voyage，which of the following is processed at the custom’s house and returned to the vessel? （）

单项选择题 When carrying a cargo of asphalt or molten sulfur，which are carried at temperatures of over 300°F，one of the biggest dangers is（）.