所有煤水(介)料桶上方必须设置篦子,篦子的孔径不得大于(),在生产过程中,篦子检查口必须密闭盖好。
A.20mm
B.15mm
C.10mm
D.5mm
参考答案:C
— Which do you like better, skating or skiing?
— _____ of them. I like running. [ ]
A. All
B. Both
C. Either
D. Neither
拉伸试验中断后伸长率修约到()。
A.1%
B.5%
C.0.5%