第13题: [单项选择]根据通风条件调整爆炸性气体环境的爆炸危险区域划分,下列说法正确的是()。 A. 当通风良好时,应提高爆炸危险区域等级 B. 可采用局部机械通风降低爆炸危险区域等级 C. 在障碍物、凹坑和死角处,应降低爆炸危险区域等级 D. 堤或墙等障碍物不能缩小爆炸危险区域的范围 参考答案:B
第27题: [单项选择]Person to person sale failed to meet the need ______. A. when the Industrial Revolution started B. when goods began to be produced in great quantities C. because trains replaced men in carrying goods around D. as attention was shifted from distribution to production 参考答案:B 答案解析:[试题分析] 考查学生对文章细节的理解。
[详细解答] 意为:“当货物批量生产时”。第二段指出,19世纪工业革命以后,产品的批量生产使得面对面的推销方式(person to person selli