单项选择题
The Chief Tally would like to inquire（）the rotation of the discharging ports.
A.at B.on C.about D.after
单项选择题 The cargo，when（），should be completely covered with plastic.
单项选择题 The cargo is liable to burn.Please keep it（）the engine room.
单项选择题 The cargo fall over the dock is called the（）.
