Ua tiav

Ua tiav

Kev kho deg yog qhov saum npoo ntawm cov khoom siv substrate los tsim ib txheej nrog cov matrix ntawm cov khoom siv kho tshuab, lub cev thiab tshuaj lom neeg ntawm cov txheej txheem txheej txheem.

kev nug nthuav dav