objective 目的，宗旨 political ～s

oblige 强迫，迫使 In certain countries the law ～s parents to send their children to school

obscure 晦涩的，费解的 an ～ text

obsolete 废弃的，淘汰的 Wooden warships are ～.

obstinate 顽固的，固执的，倔强的The girl would go her own way, in spite of all warnings

occasion 时刻，场合They met on three ～s

occupy 占用，占有My books ～ a lot of space

occur 发生，存在，出现 when did the earthquake ～?

odd的奇数的，单的，奇怪的One ,three five are ～numbers

offend 冒犯，使生气 She was afraid of ～ing anyone.

offence 犯法行为，过错 They were arrested for drug ～s.

offset 补偿，抵消They gains ～the losses.

omit 省略，删去 Minor points may be omitted.

opaque 不透明的A brick wall is ～.

option 选择权 It is your ～ to take it or leave it

orient 东方，东方国家 political theory in the West and in the Orient

origin 起源，由来 a word of Latin ～

ornament 装饰品，点缀品 We bought ～s for the Christmas tree

orthodox 正统的，正宗的 an ～ economic theory

outline轮廓，外形 He saw the ～ of a house against the sky

overflow 泛滥 Every spring the river ～s

overhaul 大修，全面检查，彻底革新～ a faulty machine

overhear 偶然听到，偷听到I wouldn’t like to be ～d

overlap 重叠，部分相同 The Renaissance overlapped the later Middle Ages

overtake 赶上，超过 He ran out of the door to ～ her

overthrow 推翻，打倒 a plot to ～ the government

overwhelm 征服，压倒，毁坏 He took 45% of the ballots and ～ed his two main rivals