Cov yam ntxwv tseem ceeb ntawm cov ntim ntim iav yog: tsis muaj tshuaj lom, tsis muaj ntxhiab; pob tshab, zoo nkauj, zoo barrier, airtight, ntau thiab ntau raw cov ntaub ntawv, uas tsis muaj nqi, thiab yuav siv tau ntau zaus. Thiab nws muaj qhov zoo ntawm kev ua haujlwm kub, siab ua haujlwm thiab tu tsis kam, ...
Nyeem ntxiv