单项选择题
When fruit is carried as refrigerated cargo，the most frequent cause of its being infected at the discharge port is（）.
A.leaks in the ship's refrigeration system B.improper cleaning of the cargo spaces C.carriage at the wrong temperature D.improper precooling of the cargo spaces
单项选择题 What additional precautions should be taken when making temporary repairs to a ship that is operating when hydrogen sulfide is present?（）
单项选择题 Ullages on tankers are measured from（）.
单项选择题 Ullages are measured from（）.
