Yav dhau los, cov ncej puab qab rooj yuav tsum tau welded artificially, lub zog wel plees, nws yuav yog ib qho teeb meem kom sib sau ua ke lub khob insulated zoo. Qee zaum nws yuav ua rau insu
Mastering txoj kev kos duab ntawm kev tswj hwm ob chav ci iav Sliding Didingdouble, muab kev sib xyaw ua ke, kev txuag hluav taws xob, thiab kev ua haujlwm zoo. Lawv ua haujlwm ua kev sib xyaw ua ke