单项选择题
The plunger may be rotated in the barrel by a rack and （） on a sleeve which is keyed to the plunger.
A.pinion arrangement B.push rod C.handle bar D.cam device
单项选择题 The plunger in the fuel injector pump, usually operated by a （）, is driven up and down when working.
单项选择题 The pistons are cooled by oil supplied from the forced （） system.
单项选择题 The piston supporting body is mainly subjected to （） stress.
