单项选择题
A.an isochronous governor B.elastic engine mounts C.a vibration damper D.a cast iron bed plate with good flexible qualities
A.(1) only is correct B.(2) only is correct C.both (1) and (2) are correct D.neither (1) or (2) are correct
A.metal particles loosened by wear B.air when no air cleaners are used C.condensation of water vapors D.breakdown of the lubricating oil by dilution