youdao

When winds blow sand particles against a large rock for a long time, the softer layer of the rock are slowly worn away.

由于风将砂粒刮起来，碰撞大岩石，久而久之，较松软的岩石层就被慢慢地磨损。(只能译成“较”，不能译为“更”)。

youdao

He carried a big stick which had seen many seasons, and a pair of sand-shoes, rather worn out.

他拄着一根年代久远的大手杖，穿着一双相当破旧的沙地鞋。

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With sections of sand, solid rock and even worn-down bridges that drivers must inspect before crossing, the 200km road takes nearly 24 hours to drive.

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And sometimes we find that vast mountains of it have been worn down by erosion and that the cassiterite is now spread through the silt and sand of an ancient estuary.

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