Kev sib dhos
Khoom siv: cov khoom sib txawv muaj.
Txheej txheem: Cov txheej txheem tsim khoom sib txawv yog 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.
