Cov lus piav qhia: Peb cov khoom yog cov khoom siv fastening zoo nrog ntau yam zoo xws li kev ua haujlwm yooj yim, siab zog, thiab kev ntseeg siab.Cov khoom siv no tsis yog tsuas yog muaj kev ua haujlwm zoo, tab sis kuj muaj cov qauv tsim zoo nkauj, ua rau nws yuav tsum muaj nyob rau hauv txhua qhov chaw tsim khoom lag luam.