| The economy in the United States is
heavily dependent on aluminum, a material widely used in the construction of
buildings and in making such diverse things as cars, airplanes, and food
containers, in 1979 Americans used over five million tons of new aluminum, and
one and a half million tons of recycled aluminum. Some ninety percent of the
bauxite (矾土) ore from which new aluminum is normally derived had to be imported
to meet the demand. Poorer ores are abundant in the United States, however, and
researchers at Purdue University may recently have found a way to obtain
aluminum magnetically from these. Although aluminum is not attracted by ordinary magnets, under special conditions it becomes temporarily "paramagnetic", or very weakly responsive to a magnetic field. This is achieved by immersing ore particles in water to which certain salts have been adde A. we can get ore particles of equal size B. we can purify aluminum particles C. we can filter out aluminum D. we can improve the working conditions around [单选题]列车进站后，应停于接车线（ ）内方。
A.警冲标 B.信号机 C.车挡表示器 D.分界标 [单项选择]耳部CT常用的扫描体位是（）
A. 横断面、矢状面 B. 矢状面、冠状面 C. 斜面、矢状面 D. 横断面、冠状面 E. 横断面、斜面 [单选题]A生产企业丢失黑火药、烟火药、引火线，未及时向当地安全生产监督管理部门和公安部门报告，由（）部门对企业主要负责人处罚款，对丢失的物品予以（）。
A.安全生产监督管理没收 B.安全生产监督管理追缴 C.公安追缴 D.公安没收 [单项选择]核酸中含量相对恒定的元素是
A. 氧 B. 氮 C. 氢 D. 碳 E. 磷 [多选题]安全监管应当针对重难点问题，拟制整治方案计划，重点明确、标准要求
A.A任务来源 B.B责任分工 C.C方法路径 D.D时间节点 E.E周边环境 [单项选择]下列分馏塔操作中，淹塔不会造成（）。
A. 塔压迅速上升 B. 侧线产品变重 C. 侧线抽出量大 D. 侧线温度上升 [单选题]《铁路旅客运输规程》规定起运地承运人依据《铁路旅客运输规程》订立的旅客运输合同对所涉及的（）具有同等约束力。
A.承运人 B.旅客 C.托运人 D.收货人 [判断题]井下不论谁发现烟气或明火等火灾灾情，应立即撤离。
A.正确 B.错误 我来回答: 提交
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