Cov khoom siv hlau yog cov khoom siv hlau hauv peb lub neej, cov khoom hlau tshwm sim txhua qhov chaw hauv peb lub neej, tab sis muaj teeb meem loj hauv kev siv cov khoom hlau, cov khoom hlau yuav tshwm sim xeb, txhua zaus xeb tshwm sim, yuav cuam tshuam rau kev siv thiab cov khoom siv hlau.Nonmetal txheej: ntxuav thiab qhuav lub sur ...
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