Dab tsi ntawm cov khib nyiab yog cov uas tsis yog lub hnab tes

Cov khoom siv rov qab xa mus rau cov ntawv pov tseg, pov tseg cov plua plav, cov khoom ntim iav pov tseg, cov ntawv hlau, pov tseg cov ntaub, thiab lwm yam, uas tsim nyog rau rov ua dua tshiab thiab rov ua dua tshiab. Cov khoom siv rov ua dua tshiab yuav tsum tau maj mam ua kom huv, huv thiab qhuav, zam kev ua qias tuaj; daim ntawv pov tseg yuav tsum nyob ncaj li sai tau; thov npliag cov ntsiab lus ntawm cov ntawv ntim ntawm peb sab, thiab flatten nws tom qab tu; yog tias muaj cov ces kaum ntse, nws yuav tsum ntim thiab muab tso rau.