单项选择题
A.a fire -tube boiler B.an internal combustion engine C.an external combustion engine D.an internal combustion generator
Shims of different thicknesses are inserted between the...
单项选择题Shims of different thicknesses are inserted between the shells to enable adjustment of （）.
A.the bearing clearances B.the bearing thickness C.the bearing strength D.the bridge hardness
Sediment collects in a tubular purifier （）.A.on top cov...
单项选择题Sediment collects in a tubular purifier （）.
A.on top cover B.on sides of bowl C.in drain line on the discs D.on the discs
Sea water is not used directly as a coolant because of ...
单项选择题Sea water is not used directly as a coolant because of （）.
A.low specific heat B.high specific heat C.corrosive action D.high viscosity
