Xws li kev dav dav ntawm cov khoom lag luam thiab lawv cov ntu.
Txhawm rau ua kom cov ntu thiab cov khoom sib txuas hloov pauv tau, cov xwm txheej hauv qab no yuav tsum tau ntsib:
, Sib hloov pauv loj;
Hauv kev ua haujlwm zoo sib xws;
Et Rov qab siv dua;
④ Tshaj tawm hauv cov qauv.
khoom
Xws li kev dav dav ntawm cov hau kev, cov txheej txheem, thiab cov cai tseev kom muaj.