Lub thawv hnyav cardboard yog dab tsi?Txhawm rau muab nws yooj yim, ntau yam khoom yog ua los ntawm ntoo raws li cov khoom ntim sab nrauv vim lawv qhov hnyav thiab ntau.Tam sim no, vim muaj ntau yam xws li kev tiv thaiv ib puag ncig, tus nqi, kev tuav thiab kev thauj mus los, cov thawv ntim hnyav tau maj mam ...