含甲醛（）的水溶液通称福尔马林。A.25~35% B.35~40% C.40~45%_爱下问搜题

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问题单项选择题

含甲醛（）的水溶液通称福尔马林。

A.25~35%

B.35~40%

C.40~45%

D.45~55%

答案

参考答案：B

选择题

From the _____ look on his face,I know he has failed in the exam. [ ]

A. disappointing

B. disappointed

C. disappoint

D. disappoints

判断题

保护地线（PE线）绝缘层的颜色是黑的。