单词：lanthanum 

名词

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  [1.n.lanthanum] (同义词:[lanthanum( n. 镧 )]  [La( [域] Lao People's Republic , 老挝人民共和国 )]  [atomic_number_57]  )
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  注释列句：a white soft metallic element that tarnishes readily; occurs in rare earth minerals and is usually classified as a rare earth
• 上位词 -> [metallic_element]  [chemical_element]  [substance( n. 物质, 实质, 主旨 )]  [matter( n. 事件, 问题, 物质, 内容, 实质, 原因, (印刷或书写的)文件, (文章或讲话等的)素材 vi. 有关系, 要紧 )]  [physical_entity]  [entity( n. 实体 )]