O字开头的单词或词组
obstructionoriginal characterorthopedicover the yearsopen-airon paperoverflowingobjectionoliveon scheduleoverwriteoccupationaloverdueon-lineofficial languageon topopen seaonwardsobviateoscilloscopeon earthon endoutlieroversideoblongobservatoryOlympusopossumon the way toout of controlof lateonce a weekon the moveoutside ofosteo-Osakaold schoolOedipusoverthrowobsceneoverjoyohmic
