硫铵蒸发结晶系统长时间停机，硫铵溶液必须稀释浓度小于（）。
A、30%
B、35%
C、40%
D、45%
参考答案：C
—What a careful boy you are!
—Thank you. In fact, Tom does everything ________ than me.
A. more carefully B. more careful C. much careless
注射用水的贮存可采用（）
A.80℃以上保温循环
B.60℃保温
C.70℃保温循环
D.65℃以上保温
E.4℃以下存放
