变压吸附停车后要把处于真空状态的吸附塔用压力较低塔（）以防止抽入空气。
参考答案：充至微正压
— Cinderella has been learning Chinese in Beijing University for the past four years .
— No wonder she ___above her colleagues in Chinese.[ ]
A. stands out
B. sticks out
C. comes out
D. sorts out
某温度下，甲、乙两个烧杯中各盛有100g相同浓度的KCl溶液，现将甲烧杯中的溶液蒸发掉35gH2O，析出晶体5g；乙烧杯中溶液蒸发掉45gH2O，析出晶体10g。则原溶液的质量分数为 [ ]
A．10%
B．15%
C．20%
D．25%
