He learnt how to clean rough ground before planting crops.

他学会了在种植作物之前如何拾掇毛糙的土地。

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Free to adjust water height and Angle, when clean rough ground, to ensure the cleaning effect.

自由调节水刮高度和角度，在清洁高低不平的地面时，确保清洁效果一致。

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They also retain the rough tongue that can help them clean every last morsel from an animal bone (and groom themselves).

它们也仍保留着那粗糙的舌头来帮助它们剔掉动物骨头上最后的一点碎屑，同时也帮助它们自己梳洗毛发。

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Rough weather since Hurricane Alex passed through the Gulf, to the south of the spill, has hampered clean-up operations for the last week.

BBC: Gulf oil spill reaches Texas as tar balls wash ashore