The area between the grooves, the ribs, supports the filter cloth and keeps it from filling the drainage holes.

凹槽中间的区域以及突起处支撑滤布并不让它堵住排水孔。

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The area between the grooves, the ribs, supports the filter cloth and keeps it from filling the drainage holes.

凹槽中间的区域以及突起处支撑滤布并不让它堵住排水孔。

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