集中式水棚的排间距为1.2-3.0m。
参考答案:对
It's time______Henry______home.[ ]
A. of, to go
B. for, to go
C. of, going
D. for, going
采用放顶煤采煤法开采时,有瓦斯或煤尘爆炸危险时,严禁挑顶煤爆破作业。