Cov txheej txheem ntawm kev hloov pauv cov khoom yas feem ntau suav nrog: txheej txheem sib xyaw, txheej txheem extrusion, ntim. Sib tov. 1. Rau qhov kev xeem ntawm kev sib xyaw: kev them nqi, txais, tu, sib faib, viav vias, sib tov. 2. Lub tshuab ntxuav: nws muab faib ua plaub qib A, B, C thiab D, uas An yog qhov siab ...
Nyeem ntxiv