第27题: [单项选择]TSP和SO2的日平均浓度数据统计的有效性是每天至少有( )。 A. 16h和18h B. 12h和18h C. 18h和18h D. 18h和12h 参考答案:B 答案解析:[解析] 对于日均值取样时间只有每天至少12h和18h的规定,这样选项A和C就可以排除了,选项B和D之间就比较好选择了。
第29题: [单项选择]Why wasn’t the young lady wearing her seat-belt A. She wasn’t able to make it fit her. B. She wasn’t able to fasten it. C. She was told not to fasten it. D. It was unnecessary to wear the seat-belt. 参考答案:A