1. Tsis txhob ua rau muaj hnub ci lossis ntau dua kev ua kom huv si: cov tawv nqaij ci ntsa iab kom tsis txhob muaj kev tshav ntuj thiab lub sijhawm no tuaj yeem ua rau cov tawv kom ua kom qhuav thiab tawg yooj yim.
2. Siv cov kws tshaj lij kev ua haujlwm: Xaiv qee tus kws tshaj lij kev ua haujlwm kom pab rov qab lub teb thiab elitteric tawv.
3. Cov khoom lag luam kom ruaj ntseg: Cov khoom tawv tawv tawv yuav tsum tau khaws cia kom qhuav thiab muaj kev tso chaw hla nrog lwm cov khoom, txwv tsis pub nws yuav ua rau hnav thiab khawb.
