单项选择题
A.safety
B.the ship, its machinery and crew
C.immediate action
D.the engineer in charge
单项选择题 There will usually be summaries or daily account tables for heavy oil, diesel oil, lubricating oil, and fresh water, which will be compiled（）
单项选择题 According to the principle of two stroke diesel engine, what is the number of its efficient work stroke per revolution?（）
单项选择题 Which of the following pumps will most affect oily water separator performance and give the worst result?（）