O字开头的单词或词组
outflowovershadowon saleottoon holidayon the telephoneoperationalorienteeringophthalmologyoverallsoxideonlookeroppressionovereatoxidativeolfactoryobserveron the increaseoutnumberoverstressomnivoreoo-on tapoverstateoutwardlyocelotover-orificeout of dangeroutward-boundob-onerousorthopedicsorthogonalon leaveolefinoutside loopoximeteroutput powerOregonophthalm-oatmeal
