Muaj ntau ntau hom kev sib xyaw ua ke hauv cov khau khoom lag luam, thiab hom thiab cov khoom siv kuj txawv. Cov khoom siv khau khiab ib txwm siv feem ntau siv cov kua nplaum dej, uas yog qhov nyuaj hauv cov txheej txheem, tus nqi siab ntawm shoemaking, tsis zoo huab cua permeability, thiab tsis zoo shaping nyhuv. Tsis tas li ntawd, s...
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