Kev sib dhos

Khoom siv: cov khoom sib txawv muaj.

Txheej txheem: cov txheej txheem tsim khoom sib txawv muaj, tom qab ntawd los ntawm kev siv cov vuam sib txawv lossis sib dhos machining ..

Nto tiav: txawv deg tiav yog muaj acc rau tus neeg siv khoom xav tau.