单项选择题
A.fresh water B.sea water C.lubrication D.fuel oil
The piston supporting body is mainly subjected to （） st...
单项选择题The piston supporting body is mainly subjected to （） stress.
A.pushing B.centrifugal C.stretch D.compressive
The piston rings if found worn out （） and supplied by s...
单项选择题The piston rings if found worn out （） and supplied by shipchandler.
A.must replace B.must to be equipped C.has to be repaired D.have to be renewed
The piston rings are manufactured with a diameter （） th...
单项选择题The piston rings are manufactured with a diameter （） the bore of the cylinder.
A.larger than B.smaller than C.equal to D.none of the above
