1. Kev hloov pauv los ntawm kub txhaws: kom deb li deb tau, ua kom sov hauv chav sov, txhawm rau ua tiav lub hom phiaj, koj tuaj yeem siv qhov txuas ntxiv ntawm cov hloov pauv hloov cov yeeb nkab lossis nce lub tshuab txias kom zam qhov tshwm sim no.
2. Kev hloov pauv vim tsis muaj qhov hnyav: Xaiv lub raj mis yas nrog cov khoom sib txawv teeb meem kom ua tiav cov teeb meem zoo los txo qhov deformation thiab lwm yam tshwm sim.
Feem ntau, cov fwj yas tau siv dav hauv kev lag luam sib txawv. Raws li daim ntawv ntim khoom ntim, lawv tau txais kev nyiam los ntawm kev ua lag luam thiab muaj kev cuam tshuam tseem ceeb ntawm kev ntim khoom lag luam.
