Taw qhia: Hauv lub ntiaj teb ceev ceev ntawm kev siv tshuab, lub sijhawm yog qhov tseem ceeb. Raws li cov khoom siv hluav taws xob tau dhau los ua ib feem tseem ceeb ntawm peb lub neej, qhov kev thov rau cov ntawv luam tawm hluav taws xob zoo (PCBs) tseem nce ntxiv. Txawm li cas los xij, qee zaum, kev txiav txim nrawm yuav tsum tau muab tso, uas tsim kev sib tw rau m ...
Nyeem ntxiv