题目表示水硬度时,1德国度相当于水中含有( )CaO。A. 1mg/LB. 10mg/LC. 50mg/LD. 100mg/L表示水硬度时,1德国度相当于水中含有( )CaO。A. 1mg/LB. 10mg/LC. 50mg/LD. 100mg/L题目解答答案B. 10mg/L