单项选择题 The position of （） on the crosshead on a large diesel engine is determined by dowel pins.

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.