Tsim los ua ib feem tseem ceeb ntawm thaj chaw cob qhia sib txawv, qhov chaw cia khoom ntau thiab ruaj khov yog qhov tseem ceeb. Ob txheej txheej cia khoom muaj peev xwm loj rau kev nkag mus tau yooj yim thaum qhov kev thov hauv chaw ua si nce ntxiv. Ua tsaug rau DHZ txoj saw hlau muaj zog thiab kev tsim khoom, cov qauv ntawm cov khoom siv ruaj khov thiab muaj tsib xyoos lav.
