Kev siv cov cua txias sib xyaw ua rau txo qhov kev ua haujlwm kub ua kom cov khoom ruaj khov ntawm cov khoom zoo.
Tus tsim ob-hniav cutter tuaj yeem paub txog kev txiav bidirectional thiab txhim kho kev ua haujlwm.Cov txheej txheem qis-kub curling tuaj yeem txo qis emissions zoo.