第12题:[单选题] Relative humidity is the percentage of water vapor that is in the air as compared to the maximum amount it can hold at ______. A. a specific barometric pressure B. a specific temperature C. a specific wind speed D. any time 参考答案:B 【参考译文】相对湿度是空气中水汽含量与特定温度下空气中最大水汽含量的百分比。 【解 析】relative humidity相对湿度 barometric pressure气压