Hauv kev txiav txim siab ib txwm muaj, kho vajtse hais txog ntau yam khoom siv hlau ua los ntawm kev tsim khoom ntawm tsib hlau xws li kub, nyiaj, tooj liab, hlau thiab tin. Niaj hnub no, nrog kev txhim kho ntawm cov hlau smelting technology thiab kev loj hlob sai ntawm tib neeg, cov khoom siv kho vajtse muaj ntau hom, xws li cov cuab yeej kho vajtse, cov khoom siv kho vajtse, cov khoom siv niaj hnub, cov khoom siv kho vajtse thiab cov khoom siv ruaj ntseg. Lub hnab ntim khoom zoo li cas yog siv rau kev ntim khoom ntawm cov khoom siv kho vajtse thiab cov khoom hlau?
Rau kev ntim khoom kho vajtse, ob hom hnab feem ntau yog siv: ib qho yog lub hnab tiv thaiv xeb, thiab lwm yam yog lub hnab nylon. Ob hom hnab no muaj cov haujlwm sib txawv. Hauv tshooj dhau los, peb tau qhia txog lawv cov yam ntxwv ntawm lub hom phiaj. tsis muaj kev piav qhia ntxiv
Nyob rau hauv luv luv, thaum ntim khoom kho vajtse, tus txheeb ze ntim lub hnab yuav tsum tau siv nyob rau hauv ua ke nrog nrog rau tiag tiag siv ntawm cov khoom, thiaj li mus cuag cov nyhuv ntawm zoo meej ntim thiab txuag nqi.
