1. Txhim kho cov txheej txheem ntau lawm
Cov txuas txuas piv rau cov txheej txheem sib dhos ntawm cov khoom siv hluav taws xob. Nws tseem yooj yim dua cov txheej txheem huab hwm coj ntau lawm;
2, Kho yooj yim
Yog tias cov khoom siv hluav taws xob tsis ua tiav, cov khoom siv tsis ua tiav tuaj yeem hloov sai sai thaum tus txuas txuas;
3, Yooj Yim los txhim kho
Raws li cov kev siv thev naus laus zis, cov khoom siv tuaj yeem hloov kho nrog cov txuas, hloov cov qub nrog cov tshiab, cov khoom siv ntau dua;
4, Txhim kho kev tsim qauv yooj yim
Kev siv ntawm cov khoom siv txuas muab rau cov kws ua haujlwm ntau dua qhov tsim nyog thaum tsim qauv thiab tsim ua ke cov khoom tshiab, zoo li thaum tsim cov khoom siv nrog cov khoom siv.