Streeter-Phelps模式研究的是()。
A.DO和COD间的关系
B.COD和BOD间的关系
C.DO和BOD间的关系
D.溶解氧的浓度
参考答案:C
The doctor recommended that you _____ swim after eating a large meal.[ ]
A wouldn't
B couldn't
C needn't
D shouldn't
装运液化石油气和其他易燃易爆化学物品的专用码头,与其他物品码头之间的距离不应小于最大装运船舶长度的( )。
A.2倍
B.3倍
C.4倍
D.5倍