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Cov lus qhia cov lus qhia rau ib nrab txuas ntxiv undergount cov drawer swb
Kev Ntsuas: Paub meej cov tub rau khoom thiab txee qhov ntev rau kev sib tw ntev ntev (feem ntau 10-18 ntiv).
Kho: Kos cim Symmetric cov haujlwm ntawm cov tub rau khoom nkag hauv qab thiab cov kab txee kom ua kom muaj zog.
Ruaj Ntseg: Sau cov xaub rau ob lub tub rau khoom thiab txee rau cov chaw tsim tshuaj paus - teev cov screats-xoob fittings ua rau jamming.
Kuaj: Tom qab kev teeb tsa, kos tias lub tub rau khoom qhib mus rau ib nrab txuas ntxiv thiab kaw kom zoo