单项选择题
A.6 B.8 C.10 D.12
A.40~60% B.40~70% C.40~80% D.50~70%
A.13 B.14 C.15 D.16
A.飞溅润滑 B.油环润滑 C.滴油润滑 D.气体润滑
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