Txawm hais tias hom kev tsim kho thiab cov khoom siv ntawm lub qhov rooj, pob khawm raug suav tias yog nws txoj haujlwm ua haujlwm. Yog tsis muaj lawv, nws tsis tuaj yeem qhib lossis kaw qhov rooj. Yuav luag txhua zaus, cov loops txiav ib yam. Tab sis tseem muaj kev zam, thaum muaj qee cov ntsiab lus tam sim no, nyob ntawm cov cuab yeej ntawm cov fittings. Dab tsi ntawm qhov rooj hinges muaj? Yuav ua li cas rau nruab lawv koj tus kheej kom raug? Peb yuav npog tag nrho cov no hauv peb tsab xov xwm niaj hnub no