Lub tshuab ziab khaub ncaws yog ib qho khoom siv tsis yog cov qauv ntsiab lus: Tsis yog-tus qauv tshuaj tsuag tshuab ziab khaub ncaws Tam sim no, tus naj npawb ntawm cov lag luam thiab cov nplais ntawm cov tshuaj tsuag kom qhuav kev lag luam hauv Suav teb yog maj mam nce. Cov tuam txhab tsim khoom tseem ceeb yog cov tshuab tshuaj, tshuaj machinery, khoom noj khoom haus, thiab lwm yam. Txawm li cas los xij, ...
Nyeem ntxiv