1. Tshawb xyuas seb lub ntim puas zoo ua ntej siv, thiab xyuas cov khoom ntim sab nrauv, hnub tsim khoom, thiab hnub tas sij hawm, thiab siv nws nyob rau hnub tas sij hawm ntawm cov khoom.
2. Cov ntaub qhwv elastic yog cov khoom siv ib zaug, thov tsis txhob rov siv dua.
3. Cov khoom no tsis nyob rau hauv kev sib cuag nrog lub qhov txhab.
4. Ua ntej siv cov khoom no, qhov dav thiab nruj yuav tsum tsim nyog. Nws yuav tsum tsis tsuas yog muab lub zog khi rau ntawm lub qhov txhab hnav khaub ncaws lossis ceg ceg, tab sis kuj tsis cuam tshuam rau cov ntshav ncig ntawm cov ceg.
5. Cov khoom no yog qib zoo tib yam thiab tsis ua kom tsis muaj menyuam. Cov neeg siv tuaj yeem txiav txim siab seb puas yuav siv nws tom qab ua kom tsis muaj menyuam raws li lub hom phiaj.
6. Tom qab siv cov khoom, nws yuav tsum tau muab pov tseg raws li qhov yuav tsum tau ua ntawm lub tsev kho mob lossis lub tuam tsev tiv thaiv ib puag ncig.
