单项选择题
A.one meter from the tank bottom and one meter below the tank top
B.one half the ullage of the tank and one meter below the tank top
C.one half the ullage of the tank and one meter above the tank bottom
D.at three meter intervals from the tank top to the bottom
单项选择题 When loading bulk liquid cargo，what is the first action you should take if a cargo valve jammed open?（）
单项选择题 When considering a vessel’s stability，which spaces in a general cargo vessel are the best locations for the carriage of bulk grain? （）
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（）.