Kuv Yuav Tsum Saib Xyuas Dab Tsi Thaum Txhim Kho U-bolts?
U-bolts feem ntau yog siv los kho cov khoom siv tubular, xws li cov kav dej lossis cov ntawv txheeb, ib yam li cov slatted springs ntawm cov tsheb tsim kev teeb tsa, cov khoom siv sib txuas, cov tsheb thauj mus los, cov choj tunnels railroads, thiab lwm yam. Cov duab tseem ceeb ntawm U-bolts yog: semi-ci...
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