Cov ntaub pua taw rooj ua los ntawm cov ris tsho qub yuav yog qhov muaj teeb meem txhim khu kev qha ntawm cov plag tsev txias thiab ob txhais ceg.
Cov ntaub pua taw rooj ua los ntawm cov ris tsho qub yuav yog qhov muaj teeb meem txhim khu kev qha ntawm cov plag tsev txias thiab ob txhais ceg.