单项选择题
A.ff overheat is found, the engine must be stopped for inspection
B.Much heat of the crankcase door indicates that the bearing is overheated
C.If bearing clearance is too large, knocking will be heard in the crankcase
D.If bearing clearance is too large or too small, the white metal may be melted
单项选择题 As to the piston cooling, of the following, which statement is not true?（）
单项选择题 The essential part of the diesel engine, whose function is to convert the heat energy into the mechanical power, is the （）.
单项选择题 Among the main propulsion units on board the ship with the same capacity, the lightest one is（）.