检识麻黄碱的方法有（）
A.二硫化碳-硫酸铜反应
B.氯化汞沉淀反应
C.过碘酸乙酰氧化丙酮缩合反应
D.茚三酮反应
E.漂白粉显色反应
参考答案：A
如何提高转化炉热效率？
Fire protection regulations for towing vessels require any fuel line subject to internal head pressure from fuel in the tank to（）.
A.be fitted with a positive fuel shut-off valve located at the tank
B.have a shut-off valve at the top of the tank
C.have a gate valve easily accessible in the space where the tank is located
D.have a drain cock at the lowest point in the fuel line
