凝结水硬度≤（）μmol/L，溶解氧≤（）μg/L。
参考答案：2.0；50
The Chinese government has made the Mid-autumn festival a national holiday,_____ people will have a day off.
A．when
B．which
C．where
D．what
道德评价的标准（）。
A.美与丑
B.虚与实
C.公与私
D.善与恶
E.人与物
