黑斑，瑕疵黑块或黑斑，如磨光的石头上的黑斑。

A dark region or blemish, as on a polished stone.

youdao

黑斑，瑕疵：黑块或黑斑，如磨光的石头上的黑斑。

A dark region or blemish, as on a polished stone.

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奔流不息的河水，随着时间流逝，能够将边缘锋利的石头打磨光滑，与此类似，洋流也可以将冰块的边缘打磨圆润。

Just as the relentless movement of water in rivers and streams can smooth the jagged edges of rocks over time, ocean currents can smooth ice fragments into round shapes.

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钻石在被切割和磨光以前，人像钻戒上的钻石那样闪闪发光——它们看看起来更像一块块深灰色的小石头。

Until diamonds are cut and polished, they do not sparkle like those you see on a ring-they just look like small, blue-grey stones.

youdao

钻石在被切割和磨光以前，人像钻戒上的钻石那样闪闪发光——它们看看起来更像一块块深灰色的小石头。

Until diamonds are cut and polished, they do not sparkle like those you see on a ring-they just look like small, blue-grey stones.

youdao