A.5% B.10% C.15% D.20%
A.滚动轴承 B.含油轴承 C.滑动轴承 D.都行
A.来煤的接受 B.粉碎 C.配合 D.混匀
A.120 B.150 C.215 D.300
A.60° B.90° C.120° D.180°