A.HRB400 B.HRBF335 C.HPB300 D.HRB335
A.沿水流方向單位長(zhǎng)度上的水頭差 B.兩點(diǎn)之間的水頭差 C.起點(diǎn)與終點(diǎn)間的水頭差 D.以上說(shuō)法均不正確
A.HRBF500 B.HPB300 C.HRB400 D.RRB400W