低压锅炉水处理中把（）叫做总硬度。
参考答案：钙、镁离子的总含量
He speaks very good English but he knows ___________ English people. [ ]
A. few
B. little
C. a few
D. a little
我国历史上第一次公布成文法的活动是()
A.铸刑书
B.邓析的“竹刑”
C.铸刑鼎
D.《法经》
