词典释义：
释义
moving to a higher (or lower) social class; acquiring (or losing) wealth and status
向更高（或更低）社会阶层流动的；获得（或失去）财富和地位的。
双语例句
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Middle-income blacks are downwardly mobile. Why?
黑人中产阶级正在不断下滑，为什么？