单项选择题
Engine displacement is equal to the cylinder （）.
A.area times the stroke B.area times the stroke, times the number of cylinders C.volume times the stroke D.volume times the stroke, times the number of cylinders
单项选择题 Auxiliary boilers are divided into several classifications, one of which is （）.
单项选择题 Load control on a diesel engine is accomplished by （）.
单项选择题 When reassembling the bowl of a disk-type centrifuge, the bowl or locking ring is rotated （）.
