Ib qhav sab hauv uas muaj qhav hluav taws yog ib hom qhav tsim nyog rau saum npoo ntawm kab tuab, uas siv ib qhov chaw hluav taws sab hauv los ua kom tsis txhob hlavs thiab tiv thaiv kev nplha thaum cai khoom yaj lossis khoom hnyuav, paub kom khaws cov khoom hlo li thiab cov khoom zoo.
