A.0.25 B.0.30 C.0.35 D.0.45
A.冷凍水管、消防管 B.冷卻水管、排水管 C.冷凍水管、冷卻水管、冷凝水管 D.冷凍水管、給水管、排水管
A.30ΩB.40ΩC.50ΩD.60Ω