— ____________ does a fish live?
— In a river. [ ]
A. Where
B. What
C. Whose
答案:A
已知在DN150mm钢管内水的流速为0.40m/s,DN150mm铸铁管的校正系数为0.90,则在相同流量下DN150mm铸铁管内水的流速为0.36m/s。
茶叶可持续发展