Kho khoom siv
(1) Txheeb xyuas seb qhov khoom loj puas tseem nyob hauv qhov tseeb ua ntej siv;
(2) Yog tias tus pin hnav zoo heev, nws tuaj yeem kho los ntawm kev sib tsoo; yog hais tias tus baffle, tus pin thiab qhov muab tso rau lub khob hlaws tus pin tau hnav tawm, nws tuaj yeem rov ua dua tshiab, thiab feem siv hnav tuaj yeem siv tom qab staggered;
(3) Los tiv thaiv xeb roj yuav tsum tau thov tom qab siv tas.