Kev ua kom cov npoo hlau puag ncig yog cov txheej txheem ntawm kev tshem tawm cov npoo ntse lossis cov npoo burr ntawm cov khoom hlau kom tsim tau ib qho chaw du thiab muaj kev nyab xeeb. Cov tshuab sib tsoo slag yog cov tshuab ruaj khov uas sib tsoo cov khoom hlau thaum lawv raug pub los ntawm, tshem tawm tag nrho cov slag hnyav sai thiab zoo. Cov tshuab no siv ntau txoj siv sib tsoo thiab txhuam kom yooj yim rhuav tshem txawm tias cov khib nyiab hnyav tshaj plaws.
