Hauv kev tsim kho, cov kav hlau steel, uas yog cov khoom siv tseem ceeb, tau siv dav hauv ntau yam engineering xws li txuas hniav, cov tsev siab siab, thiab cov nroj tsuag muaj kev lag luam. Cov kav hlau tsis yog tsuas yog nqa qhov hnyav ntawm lub tsev tab sis kuj muaj feem xyuam rau tag nrho cov kev ruaj ntseg thiab kev nyab xeeb ...
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