Most shallow aquifers in sand and gravel deposits produce lower yields, but they can be rapidly recharged.

"大多数沙石中较浅的蓄水层贮水量少，但可以迅速再生。

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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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The workers mixed the asphalt with sand and gravel together.

工人们把沥青和沙子、石块混合在一起。

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This plant turns debris from buildings - many destroyed by Israeli air strikes - into sand and gravel that is then turned into cinder blocks for building.

VOA: standard.2010.06.16

The quarry is owned and run by Cemex, which extracts sand and gravel from the site.

BBC: Kingsmead Quarry 'beaker burial' woman is rare find

If approved the quarry would release five million tonnes of new sand and gravel reserves.

BBC: Ducklington's Gill Mill quarry expansion planned

Major activities in the area are agriculture, forest management, sand and gravel extraction, industry (diverse types), and ecotourism.

UNESCO: EDUCATION