海水淡化装置中开始生成硫酸钙CaSO4硬垢的条件是（）。A.工作温

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问题单项选择题

海水淡化装置中开始生成硫酸钙CaSO4硬垢的条件是（）。

A.工作温度高于75℃

B.真空度小于90％

C.盐水浓缩率大于1.5

D.给水倍率大于3~4

答案

参考答案：C

选择题

Not only _______ interested in football but _______ beginning to show an interest in it. [ ]

A. the teacher himself is, all his students are

B. the teacher himself is, are all his students

C. is the teacher himself, are all his students

D. is the teacher himself, all his students are

判断题

在机场控制区内不可擅自动用明火。