芒硝的主成分是() ["A.含水硫酸钠","B.含水硫化汞","C.硫化钙","D.硫化砷","E.三氧化二砷"]
某架空送电线路给定离地高10m高的基准设计风速v=30m/s,求离地高20m高时的基准风压()。 ["0.563kN/m2","0.411kN/m2","0.703kN/m2","0.432kN/m2"]
卡马西平() ["对癫痫强直阵挛性发作疗效好,为首选药","对癫痫复杂部分性发作有良效,为首选药","对失神性发作疗效最好,强于乙琥胺","仅对失神发作有效,为首选药","对于癫痫持续状态为首选药"]
据史书《三铺决录中记载》;“夫工欲善其事,必先利其器,用张芝笔、左伯纸及臣墨。”这段文字反映出当时出现的()广告形式。
赭石的主成分是() ["四氧化三铁","碳酸锌","氯化亚汞","二硫化铁","三氧化二铁"]
跌落式熔断器应安装在行车道()或()方向。