单项选择题 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.

单项选择题 “lover-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（）

单项选择题 If the gas pressure behind the ring is built up too slowly, and thereby exerts an inadequate outward pressureIn such a case, the combustion gas can penetrate between the liner and ring, and violently force the ring inwards, in the grooveWhat result will this type of sudden "shock" loading eventually lead to?（）