Kev ua lag luam uas tsis yog-rotating hlau hlua yog tsim kom muaj kev loj hlob ntau, uas tau tsav los ntawm kev xav tau los ntawm ntau yam kev lag luam xws li cranes, hluav taws xob hoists, thiab ropeways. Raws li kev lag luam ua qhov tseem ceeb ntawm kev nyab xeeb, kev ua haujlwm thiab kev ntseeg siab, qhov xav tau rau cov hlua hlau zoo...
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