单项选择题
A.a high exhaust temperature B.a high smoky exhaust C.a high output D.a high compression
Each piston stuffing box is provided with two sealing r...
单项选择题Each piston stuffing box is provided with two sealing rings and three（）
A.packings B.piston rings C.distributor rings D.scraper rings
Each journal and pin should be examined for （） and groo...
单项选择题Each journal and pin should be examined for （） and grooving.
A.bridges B.recesses C.rears D.ridging
Each cylinder liner on the marine medium speed engines ...
单项选择题Each cylinder liner on the marine medium speed engines （）.
A.is usually cooled by sea water B.can be replaced when worn out C.is in direct contact with the water in the bore of the cylinder D.can t expand when heated
