O字开头的单词或词组
ovaobservingolive oilopportuneoverrunon account ofoutreachoutliveoccupationaloffice workeron saleoutflowonomatopoeiaOkieon-lineon creditobtuseohon arrivalorchardorthopedicold schoolobbligatooustoligo-operationalotherwiseowe sth to sboutskirtson the horizonorder numberon the trackoveruseoff and onoverflewover the yearsoverplayoil filteroutrightoff guardonce and for alloverdose
