O字开头的单词或词组
on one's own accountoversimplifyoutsizeoccidentouterwearonce moreoofoverridingorthodonticsoutburstoutshineozone layerOSFovertookoff-lineof noteout of boundsowner's capitalother oneOrientalismoriginationopt forout of pocketoff-dutyO2on...basisonce or twiceoratoryobstetricovertoneOPD.odorlessoddballoperation manualoccludeold stockOlympiaoutpouringopenlyobsequiousoral examinationoneness
