单选题:The electrostatic precipitator has got rid of___________from 题目分类:英语六级 题目类型:单选题 查看权限:VIP 题目内容: The electrostatic precipitator has got rid of___________from manufacturing processes. A.severe emissions B.ozone-layer depletion C.many pollutants D.toxic substances 参考答案: 答案解析:
Questions are based on the passage you have just heard.请作答__ Questions are based on the passage you have just heard.请作答______A.In 1938 B.In 1 分类:英语六级 题型:单选题 查看答案
Directions:In this section,you will hear 3 short passages.At Directions:In this section,you will hear 3 short passages.At the end of each pas 分类:英语六级 题型:单选题 查看答案
能够区分盐酸吗啡与磷酸可待因的试剂为 能够区分盐酸吗啡与磷酸可待因的试剂为A.稀铁氰化钾试液 B.氨试液 C.甲醛硫酸试液(Marquis试液) D.铜吡啶试液 E.钼硫酸试液 分类:英语六级 题型:单选题 查看答案
下列鉴别反应中,属于吡啶开环反应的是 下列鉴别反应中,属于吡啶开环反应的是A.甲醛-硫酸反应 B.硫色素反应 C.芳伯氨基反应 D.硫酸荧光反应 E.戊烯二醛反应 分类:英语六级 题型:单选题 查看答案