The commonest spaces are those among the particles—sand grains and tiny pebbles—of loose, unconsolidated sand and gravel.

最常见的空间是那些由松散的、未固结的砂和砾石组成的颗粒（沙粒和小卵石）之间的空间。

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Bar: fully or partially submerged mound of sand, gravel or other unconsolidated material built on the sea-bottom in shallow water by waves and currents.

UNESCO: L O S S A R Y