Ua ntej siv lub tshuab vuam tshuab, nws yog ib qho tseem ceeb uas yuav tsum tau ua raws li qee qhov kev ceev faj kom muaj kev nyab xeeb, kev ua tau zoo, thiab kev ua haujlwm zoo. Kab lus no tham txog cov ntsiab lus tseem ceeb thiab cov kauj ruam uas cov neeg ua haujlwm yuav tsum ua ua ntej siv lub tshuab welding kom tsis txhob muaj xwm txheej, txo qhov yuam kev, ...
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