Txawm hais tias muaj ntau lub tsheb siv 4157nak qhov muag teev, Kuv paub tseeb tias cov neeg feem coob tsis paub tias qhov teeb meem li cas txog 4157nak qhov muag teev.

Kuv xav muab lus piav qhia txog 4157nak noob li hauv qab no.

“Na” txhais tau hais tias amber xim.

“K” txhais tau tias muab krypton roj rau hauv 4157nak noob.

Muab piv nrog tus qauv 4157 lossis 4157na noob, 4157nak noob yog lub neej ntev dua.

Yuav ua rau koj kom meej meej 4157nak qhov muag teev, kuv yuav muab cov duab rau koj cov ntaub ntawv.

Daim duab hauv qab no yog 3157nak noob, uas yog tib yam li 4157nak noob.