在搬运射孔器、设备前，要对所经路径和摆放场所的杂物及湿滑地面如何处理？
参考答案：
将杂物挪开，用干土或草垫覆盖湿滑路面。
—How do you feel your travel to Hainan?
—________，I enjoyed it very much，although the weather of some days was unpleasant.
A．In addition
B．On the whole
C．In other words
D．On the other hand
主扇风量为15000m3/min，通风阻力应小于（）Pa。
A.3920
B.2500
C.2940
D.4930
