Cov qauv sau ntawv yog ib feem ntawm kev tshawb fawb ntawm hom lus. Ib feem tseem ceeb heev vim nws kawm txog cov qauv sau ntawv ntawm lub hauv paus rau kev tsim cov kab lus, cov qauv tsim ntawm ntau cov kab lus thiab kab lus, txo cov qauv no rau hauv ib qho kev cai ntawm kev cai