Dab tsi yog qhov tseem ceeb ntawm lub tsheb saib iav?
1. Lub qhov iav pom kev tuaj yeem ua rau pom kev ntawm tus tsav tsheb.
2. Tsom iav pom daim duab qhia txog qhov teeb meem nyob tom qab, sab thiab hauv qab ntawm lub tsheb, ua tus tsav tsheb pom cov xwm txheej ntawm cov haujlwm no. Nws ua raws li "ob lub qhov muag" ntawm tus tsav tsheb.
Ntawm no yog qee qhov kev sib txuas ntawm cov tsheb npav tsheb saib xyuas peb cov khoom lag luam hauv ECO, koj tuaj yeem pom zoo rau koj siv:
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