单项选择题
Main propulsion engine lube oil sumps should be constructed （）
A.so as to never be integral lube B.with a sloped bottom C.only of nonferrous, noncorrosive metals D.with drain/return lines terminating just above or at the designed normal level
单项选择题 The ash content of a fuel oil is significant to the operating engineer because it （）
单项选择题 The shape of a cam on a diesel engine determines the valve’s （）
单项选择题 Which of the listed devices could be used as a ring groove tool during preparation for the installation of new rings?（）
