Muaj ntau cov phuam ntub tam sim no siv nyob rau hauv kev ua lag luam feem ntau siv cov phuam ntub dej los yog cov phuam ntub huv huv, thiab lawv cov ntsiab lus yog sib txawv ntawm cov phuam ntub dej tsis huv. Yog li, cov ntaub ntub dej yuav tsum xaiv cov khoom siv kom tsim nyog thiab raug ua ntej siv. Nov yog yuav ua li cas xaiv txoj phuam uas ntub dej.
Ntub tshuab ntub dej Yuav ua li cas xaiv cov kev tshaj lij kev faib tawm ntawm cov ntaub so ntub. Cov ntaub ntub dej tsis zoo siv cov ntaub tsis muaj ntaub, cov ntaub, cov ntawv tsis muaj hmoov av lossis lwm cov ntaub ntawv raw li cov neeg nqa khoom, dej ntshiab li cov dej ntau lawm, thiab cov khoom txuag tsim nyog thiab lwm cov ntaub ntawv pabcuam, khoom siv, tawv nqaij ua paug lossis cov khoom lag luam nrog kev ua kom huv ntawm lub ntsej muag. Cov. Cov ntaub so huv siv cov ntaub tsis muaj ntaub, cov ntaub, cov ntawv tsis muaj hmoov av lossis lwm cov ntaub ntawv raw li cov chaw thauj khoom, cov dej huv raws li cov khoom tsim thiab cov dej nyob, thiab cov nqi tsim nyog ntawm cov khoom txuag thiab lwm cov khoom siv tiv thaiv. Cov tes, tawv lossis cov khoom tsim nyob rau saum npoo av los tsim tu thiab ua kom huv. khoom.