单项选择题
A.the guideway
B.the piston rod
C.the crosshead shoes
D.the interlocked circlip
单项选择题 The ports are drilled in the liners at an angle of approx 20℃ the result being that （） is given a rotary movement.
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.
单项选择题 The plunger in the fuel injector pump, usually operated by a （）, is driven up and down when working.