Most moons are either round and smooth, or lumpy pieces of space rock.

大多数卫星要么是圆形的，要么是光滑的，要么是块状的太空岩石。

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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.

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。

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All the stones are smooth and round, telling an endless of history of water steadily forming and reforming the cave's interior.

所有的石头都十分圆滑，这是水长年累月对岩洞内部不断冲击和打磨的结果。

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Dubbed Pebble for its smooth, round shape, the gadget lends itself to impromptu games of catch and prompts contemplative gazing while nestled in the palm.

FORBES: Samsung S2 Pebble

Spost advocates choosing a fairly round, smooth pumpkin and using some basic tools to bring your jack-o'-lantern to life.

CNN: Carving up a spooky Halloween

She turned on her side to better look at it, and noticed for the first time how comely it was, how round and smooth were its face and shoulders and belly, how lustrous was its hair.

NEWYORKER: A Tiny Feast