O字母开头的单词或词组(第10页)：

• onion
• optimistic
• option
• or
• oral
• orange
• orbit
• order
• orderly
• organ
• ordinary
• organization
• organize
• origin
• originate
• ornament
• other
• otherwise
• ought
• ounce
• our
• ours
• ourselves
• out
• outbreak
• outdoors
• outgrow
• outcome
• outlook
• outside
• output
• over
• overcoat
• outstanding
• overcome
• overhead
• overnight
• oversea
• overtake
• overtime
• overwork
• owe
• owing
• own