压缩机的无油润滑是指在()部分,用自润滑材料制造活塞环等配件,不需再加油润滑。
A.气缸~活塞
B.活塞~填料函
C.气缸~填料函
D.传动机构
参考答案:A
—I’m fed up with these naughty boys!
—Maybe we can find a new direction for their _________ energies. How about a football game?
A.abundant
B.abnormal
C.aggressive
D.alternative
预应力钢筋的强度标准值,应具有不小于()%的保证率。
A.100
B.95
C.85
D.80