建筑安全技术
2台蛙式打夯机同时作业时,左右间距不小于( )m,前后不小于( )m。
A.2;5
B.4;10
C.5;10
D.6:12
参考答案:C
"Life is like walking in the snow", Granny used to say, "because every step ________."[ ]
A. has shown
B. is showing
C. shows
D. showed
火焰能率是以每小时消耗氧气的多少来计算。