A.5m B.10m C.15m D.20m
A.5%~10% B.10%~20 C.20%~30% D.30%~40%
A.風(fēng)管式通風(fēng) B.巷道式通風(fēng) C.對(duì)流式通風(fēng) D.風(fēng)道式通風(fēng)