单项选择题
A.锅炉汽包B.给水管道C.水冷壁管D.凝结水管道
A.20-50ug/LB.10-50ug/LC.20-40ug/LD.15-50ug/L
A.100ug/kg ;50ug/kgB.100ug/kg ;20ug/kgC.100ug/kg ;30ug/kgD.80ug/kg ;50ug/kg