1. Nws tuaj yeem hloov cov palicon hlau hmoov li cov khoom siv refractory, uas tuaj yeem txo cov nqi tsim.
2. Nws muaj ntau txawm tias qhov loj me me.
3. Nws muaj kev ua tau ruaj khov thiab kev pabcuam txuas ntxiv lub neej ntawm cov khoom lag luam refractory.
