单项选择题
A.1 B.2 C.0
A.矿尘 B.风压 C.风阻 D.空气压力
A.1 B.2 C.3
A.4h B.8h C.12h D.24h
A.3.5 B.2 C.10
A.3，6 B.6，3 C.6，6
A.0.00025% B.0.0024% C.0.00066% D.0.004%
A.0.00025% B.0.0024% C.0.00066% D.0.0005%
A.1mm B.10um C.5um
A.一B.二C.三D.零
A.高温强辐射 B.高温高湿 C.露天
