关于硫酸铝的说法错误的是（）
A.硫酸铝易溶于水
B.水溶液呈酸性
C.在正常状态下无结晶水
D.无水硫酸铝为白色结晶体
参考答案：C
—Do you know when we can go back home?
—Sorry, I don’t. Because of the heavy snow storm, highways have been blocked and flights have been __________.
A．put up
B．put off
C．taken off
D．taken up
压裂液的砂比是指支撑剂的体积与携砂液的体积的比值。
