Yog vim li cas rau cov dej tsis txaus ntawm cov twj tso kua mis tob
Thaum siv lub twj tso kua dej sib sib zog nqus, qee zaus yuav muaj dej tsis txaus, tsis muaj dej tawm, thiab nqa qis. Yog li, dab tsi yog qhov ua rau ntawm qhov xwm txheej no? Muaj peb qhov laj tha...