strata [ˈstretə, ˈstrætə]

例句:

• The rebels came overwhelmingly from the poorest strata of rural society.
  叛乱分子绝大多数来自农村的最贫困阶层。
  来自柯林斯例句
• The older strata gradually disintegrate.
  较老的岩层渐渐风化.
  
• people from all social strata
  来自不同社会阶层的人
  
• The water would gain admission to the saline strata.
  来自J. Playfair
• It is profoundly embedded into every strata of existence.
  来自SA
• They come from all strata of Paris society.
  来自WSJ