單項(xiàng)選擇題

The cylinder oil is pumped into the cylinder (via non-return valves) when the piston rings pass the lubricating orifices during （）

A.the upward stroke
B.the downward stroke
C.the power stroke
D.the suction stroke

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單項(xiàng)選擇題

If there are micro-seized areas on the liner or skirt scratch-over manually with a coarse carbo-rundum stone (grindstone), moving the grindstone （） at an angle of 20 to 30 degrees to horizontal.

A.clockwise
B.anticlockwise
C.crosswise
D.vertically

單項(xiàng)選擇題

“l(fā)over-leafing”is a term used to describe corrosive wear at several separate points around liner circumference- iein some cases the liner bore may assume a “clover-leaf”shape（）

A.transverse
B.longitudinal
C.circumferential
D.radial