Kev tiv thaiv xob laim ntawm lub substation
Rau txoj kab hluav taws xob tiv thaiv, tsuas yog yuav tsum muaj kev tiv thaiv xob laim ib nrab, uas yog, raws li qhov tseem ceeb ntawm txoj kab, tsuas yog yuav tsum muaj qee theem ntawm kev tiv thaiv xob laim. Thiab rau cov nroj tsuag fais fab, subst...
nyeem ntxiv