Pib qhia txheej txheem teeb meem thaum ub
Cov khoom sib txuas ua ke xa mus rau qhov tsawg tshaj plaws los yog / thiab cov chav tsev tseem ceeb ntawm cov teeb meem uas tib neeg paub, thiab yog lub hauv paus rau kev tsim ua ke ntawm ntau yam khoom. Ntawd yog: qhov tsawg kawg nkaus ntawm teeb meem tsis muaj hloov pauv lub zog ntawm kev ua yeeb yam. Nws yog lub hauv paus ntawm txhua yam khoom, thiab nws tsis yog vim tias nws me me tias nws tsis yog lub cuab yeej.