Cov khoom

Khoom siv & Kev tsim kho Ib daim ntawv lo txhim khu kev ntseeg yog nyob ntawm ntau- txheej txheej txheej txheem raws li daim ntawv thov substrate thiab chaw u

Khoom siv & Kev tsim kho   Daim ntawv qhia kev lag luam ua haujlwm raws li ntau- txheej txheej sib xyaw ua ke suav nrog lub ntsej muag khoom, ib qho kev xa