A.2 B.3 C.4 D.5
A.當(dāng)管徑小于等于200mm,跌水水頭大于0.2mm時(shí)。 B.當(dāng)管徑小于等于300mm,跌水水頭大于0.3mm時(shí) C.當(dāng)管徑小于等于400mm,跌水水頭大于0.4mm時(shí) D.當(dāng)管徑小于等于500mm,跌水水頭大于0.5mm時(shí)
A.8 B.9 C.10 D.11