1. compring txheej: kev tiv thaiv cov khoom siv hluav taws xob {yog ib qho khoom siv hluav taws xob tau zoo los ntawm kev cuam tshuam lwm cov khoom siv hluav taws xob lossis cov tshuab.
2. Kev tiv thaiv kev siv hluav taws xob hluav taws xob tuaj yeem ua rau cov paib hluav taws xob, tiv thaiv hluav taws xob lossis tswj hwm kev ncaj ncees ntawm lub teeb liab.
3.}}}}}}}} istince muaj peev xwm ntawm cov cim hluav taws xob ntawm cov cim hluav taws xob sab hauv sab hauv ntawm cov cim sib kis los ntawm lub cav.
{{04. Kev tiv thaiv kev nyab xeeb: thaum lub cable khib nyiab los cuam tshuam rau hauv av, yog li ua si tiv thaiv kev nyab xeeb .
5. Cov qauv kev txhawb nqa: rau ib qho xwm txheej, tooj liab ib yam, tooj liab kev txhawb nqa rau cov xaim, txhim kho lawv cov khoom siv zog.
