oath
n. solemn， formal declaration or promise to fulfill a pledge， often calling on God or a sacred object as witness 誓约，宣誓 an imprecation； a curse 咒骂；诅咒语
make/take an oath 立誓，宣誓/be on oath 宣誓不作伪证/on one s oath 发誓
Before giving evidence the witness had to take an oath.
证人在做证前要先宣誓。
obedient
adj. dutifully complying with the commands，orders，or instructions of one in authority 服从的，孝顺的
Your (most) obedient servant 拜上；谨启(等)(信尾用语)
In some countries， students are expected to be quiet and obedient in the classroom.
在某些国家，在课堂上期望学生们保持安静，并且顺从。（2001年1月阅读理解）
Students are expected to be quiet and obedient in an Asian classroom.
在亚洲学生在教室里必须安静和听话。
obligation
ｎ. a social， legal， or moral requirement， such as a duty， contract， or promise that compels one to follow or avoid a particular course of action 义务，社会责任 the service or favor for which one is indebted to another 恩惠
后接to sb.(sth.)或to do sth.后者表示“应该做”。
obligation， duty
obligation 指道义上或法律上的义务，有契约的意味；如：We are under no obligation to give him what he wants. 我们没有义务向他提供他所需的东西。 duty 指道义上的责任，比较强调自觉性。如：Did you do your duty as a responsible citizen？ 你是否尽到了一个负责人的责任？
a legal (moral) obligation 法律上(道德上)的义务/a citizen s obligation to the state 公民对国家的义务/fulfill one s obligation 尽义务/repay an obligation 报恩
Father was not a wealthy man， but he always fulfilled his financial obligations.
父亲不是个富人，但他总是尽他经济上的义务。
obscene
adj. (of words， thoughts， books， pictures， etc.) indecent， esp sexually； disgusting and offensive； likely to corrupt （指词语、思想、书画等）下流的，（尤指）淫秽的，猥亵的，可憎的，伤风败俗的
obscene language下流的语言/an obscene picture 一幅淫画/an obscene publication （律）伤风败俗的刊物；淫书
The way he writes about the disease that killed her is simply obscene.
他描写夺去女孩生命的疾病的手法，令人恶心。
obscure
adj. inadequately supplied with light 模糊的，不清楚的 hard to understand 费解的 not well known 不很著名的 vt.to hide 隐藏 to make difficult to see 使不清楚，使费解
obscure， vague
obscure 指某物的意思复杂、深奥或未明确表达出来，使人晦涩难懂。如：That passage is obscure to us.那段文章我们难以理解。 vague 指言词不确定或太笼统，使人不能完全猜透其意。如：His explanation was vague.他的解释含糊不清。
an obscure explanation 含糊不清的/an obscure corner 阴暗的角落/an obscure text 难解的文本/an obscure author 不著名的作家/an obscure job in the government 政府中的小职位/an obscure mountain village 偏僻的山村/an obscure idea 模糊的想法/an obscure night 黑暗的夜晚
The Second Construction (1954—1968)，or the modern civil rights movement，ended legal segrepation in public accommodations and gave blacks voting rights.But these successes paradoxically obscure the tremendous human costs of historically accumulate disadvantage that remain central to black Americans lives.
第二次重构（1954—1968），也叫做现代民权运动，使公共住宅区内的合法隔离不复存在，并使所有黑人都获得了选举权。但与此矛盾的是，这些成功却掩盖了由于历史上长期积累的不利因素而使黑人付出的巨大代价，而这种不利因素在美国黑人生活中仍然处于中心地位。(2006年6月阅读理解)
Very few people understood his lecture， the subject of which was very obscure.
很少有人会理解他的演讲，因为其题目十分晦涩。
odor
n. the property or quality of a thing that affects， stimulates， or is perceived by the sense of smell； esteem； repute 气味，名声
body odor 体臭/a pleasant odor 怡人的香味/a strange odor 奇怪的气味/a sweetscented odor 芳香/produce an odor 产生某种气味/perceive an odor 觉察某种气味/be in good/bad odor with sb. 声誉好（坏）
A horrible odor filled the place. 这个地方充满了令人不快的气味。
offence
n. the act of causing anger， resentment， displeasure， or affront 进攻；触怒；不悦；冒犯
offensive
adj. causing anger， displeasure， resentment， or affront 讨厌的，无礼的，攻击性的 n. an attitude or a position of attack 进攻，攻势
Bad eggs have an offensive odor.
坏鸡蛋有股令人讨厌的气味。
offset
n. an agent， an element， or a thing that balances， counteracts， or compensates for sth. else 抵消；补偿 vt. to counterbalance， counteract， or compensate for 抵消；补偿
offset the cost of... 补偿……的费用/offset the disadvantage 抵消不利因素/offset one s travel expenses against tax 用旅费抵消某人的税
He has to offset his small salary by living economically.
他通过节俭的生活使工资够用。
offspring
n. the progeny or descendants of a person， an animal， or a plant considered as a group 子孙，后裔；幼兽
illegitimate offspring 私生子/sole offspring 独生子女/rear offspring 抚养子女/produce offspring 生儿育女/produce offspring 生儿育女/limit one s offspring节育
I am the offspring of a musician and a scientist.
我是一位音乐家和一位科学家的后代。
opaque
adj. impenetrable by light； neither transparent nor translucent 不透明的；难懂的；晦涩的
an opaque star light 昏暗的星光/an opaque window 一扇不透光的窗子/an opaque piece of prose 一篇晦涩难懂的散文/an opaque projector 反射幻灯机
The glass in the bathroom window is opaque.
卫生间窗户的玻璃是不透明的。
oppress
vt. to keep down by severe and unjust use of force or authorlty 压迫，压抑
oppress，suppress，repress
oppress 意为残酷地、无理地加以重压，指压迫和虐待弱者和人民等。如：A good government will not oppress the people.好政府不压迫人民。 suppress 意为凭借强力抑制，指制服叹息、呻吟、大笑、欲望、镇压叛乱，扑灭火灾等。如：The soldiers speedily suppressed the rebellion.军队很快地镇压了叛乱。 repress 意为有效地遏止，如镇压叛乱，抑制情欲、情绪、眼泪、冲动等。如：The police repressed the revolt. 警方镇压了暴乱。
be oppressed by 受……的压迫/压制/be oppressed by/with 因……(心情)沉重，烦恼
The oppressed slaves took up arms and fought against the dictator and at last choose a leader of their own.
被压迫的奴隶们武装起来，打败了独裁者，最后选出了他们自己的领导人。
For years now， the people of that faraway country have been cruelly oppressed by a dictator.
这些年来，那个偏僻国度的人们一直受着独裁者的压迫。
optimism
n. a tendency to expect the best possible outcome or dwell on the most hopeful aspects of a situation 乐观，乐观主义
blind optimism 盲目乐观/extravagant optimism 过分乐观/cultivate optimism 培养乐观精神/display optimism 表现出乐观态度/unfailing optimism 始终如一的乐观主义/optimism about/over the future 对未来的乐观态度
We look to the future with optimism.
我们乐观地展望未来。
optimum
adj. best or most favourable 最佳的；最适宜的；最有利的
optimum weather conditions 最合适的气候条件，最佳气候条件/the optimum growth temperature 最适生长温度/the optimum programming 最佳程序设计
They are not functioning at their optimum.
他们并非在最有效地工作。
option
n. the freedom to choose 选择，选择自由 the right of choosing 选择权
make one s option是“做出选择”。如：It is hard to make my option between such alternatives.(要我对这样两种选择的方案做出抉择是很困难的。) exercise one s option是“履行选择权”。如：Every voter should exercise his option.(每个投票人应履行自己的选择权。)
choice，option
choice 一般用词，指可以任意选择自己喜欢的东西，强调自由选择。如：Take your choice from among those books. 那些书由你选择。 option强调从两个或两个以上互相排斥的事物中做出选择，着重强调选择的权力和自由。如：Students have the option of taking French， German， or Spanish. 学生可以选修法文、德文或西班牙文。
I have the option of accepting all or part of the money.
我有权选择接受全部或部分的线。
orient
n. the countries of Asia，esp.of eastern Asia 东方，东方诸国(尤指东亚国家)adj. eastern；oriental 东方的，上升的，灿烂的vi. to turn toward the east 适应形式，向东vt. to locate or place in a particular relation to the points of the compass 使朝东，使适应，确定方向
orient oneself 表明态度/orient oneself to one s surroundings 使自己适应环境/orient sb. to the language 使某人熟悉那门语言
Columbus went west to look for better trade routes to the Orient and to promote the greater glory of Spain.
哥伦布向西方航行以求找到到达东方的更好贸易路线，并将西班牙的光辉历史进一步发扬光大。（2001年6月阅读理解）
You can orient yourself by remembering that big hill is due north.
只要记住那座大山是在正北方，你就可以确定自己的位置了。
oriental
n. used as a disparaging term for an Asian person 东方人（尤指中国人和日本人） adj. of or relating to the countries of the Orient or their peoples or cultures； eastern 东方诸国的，亚洲的，东方的，（珍珠等）最优质的
the oriental way of life 东方生活方式/the oriental region 东方区/Oriental Jew 东方犹太人/oriental rug 手织东方式地毯
People find that the oriental way of life is becoming more and more popular in the western countries.
人们发现在西方国家日渐盛行东方的生活方式。
orientation
n. the act of orienting or the state of being oriented 方向，方位，定位，倾向性，向东方
the general orientation 大方向/give new employees an orientation 向新雇员介绍情况/a new orientation in life 生活中新的努力方向/the orientation of a wall 一堵墙的方向
The winding trail caused them to lose their orientation.
蜿蜒的小径使他们失去了方向。
originate
vt. to bring into being； create 引起，发明，发起，创办vi. to come into being； start 起源，发生
originate in/from/with 产生于……，起源于……
The quarrel originated in a misunderstanding.
争吵是由于误解而引起的。
ornament
ｎ. (sth. used for) decoration； 装饰，装饰物vt.to add beauty to 装饰，美化
ornament作“装饰品”解时，是可数名词，作“装饰”解时，是不可数名词。如：It is more for ornament than for use.(这东西主要供装饰而不是实用。)We bought ornaments for the Christmas trees.(我们购买装饰品点缀圣诞树。)ornamentornamental(a.装饰的；装饰用；装饰性的)。如：for ornamental purposes(为了装饰的目的)；an ornamental pond(装饰性水池)。
by way of ornament 作为装饰/a chair rich in ornament 装饰讲究的椅子/an ornament to one s country 为国增光的人/for mere ornament 仅仅为了装饰/without ornament 不加修饰/ornament sth. with...用……装饰某物/a palace rich in ornament 装饰华丽的宫殿
The Christmas tree was decorated with shining ornaments such as colored lights and glass balls.
圣诞树被一些闪亮的装饰物点缀着，如彩灯和玻璃球。（2001年1月阅读理解）
We went to the department store and bought ornaments for the Christmas tree.
我们去商店买了一些点缀圣诞树的装饰品。
orthodox
adj. adhering to the accepted or traditional and established faith， esp. in religion 正统的，传统的，习惯的，保守的，东正教的
the Orthodox Church 希腊教会，东正教会/an orthodox approach 传统的方法/orthodox ideas 正统观念/orthodox behavior 传统的行为/orthodox medicine 传统医学/ orthodox sleep 无梦睡眠/an orthodox economic theory 正统的经济理论
We should prefer a more orthodox solution to the problem.
我们宁愿对这问题采取更正统的解决办法。
outbreak
n. a sudden eruption； an outburst （战争的）爆发，（疾病的）发作
coldair outbreak 寒潮/a largescale outbreak 大规模（疾病）爆发/a periodic outbreak 周期性猖獗，周期性大发生/an outbreak of influenza 流感爆发/an outbreak of locusts 蝗灾突发/a volcanic outbreak 火山爆发/a sever outbreak of food poisoning 严重食物中毒的发生/an outbreak of fever 发烧/an outbreak of anger 发怒
There has been an outbreak of measles in town.
城里麻疹爆发。
oval
adj. resembling an egg in shape 卵形的，椭圆的 n. an eggshaped or elliptical form or figure 卵形，椭圆形
overflow
ｖ. to flow over the edges or limits of sth. (使)溢出，泛滥 overflowing of liquid 充满 n. a pipe that allows excess liquid to escape 泛滥，外溢(之物)；排水口，溢流管
overflow作及物动词时，作“使涨满；使泛滥”解。overflow作不及物动词时，作“充满，洋溢”解，后接with。overflow的过去式和过去分词均为overflowed。
the overflow of the river 河水泛滥/an overflow of... 大量的……/overflow with happiness/gratitude 充满幸福/感谢
The bath is overflowing； who has left the water running？
浴水正在流出，谁让水在流？
overhear
vt. to hear (speech or sb. speaking) without the speaker s awareness or intent 无意中听到，偷听
overhear the talk 无意中听到谈话/overhear the secret 无意中听到秘密
They spoke so loud that I could not help overhearing what they said.
他们讲话嗓门太大，我不得已偷听到他们说的话。
overlap
vt. &； vi. to lie over and partly cover sth. 部分重叠
overlaps the function of sth. 功能重叠/the overlapping powers 重叠的职权/the overlap of responsibilities 职责的重叠
When you put up wallpaper， should you overlap the edges or put them next to each other？
贴墙纸时，是将边相互搭叠呢还是缝对缝挨着？（2000年6月阅读理解）
History and politics overlap and should be studied together.
历史和政治有部分内容重叠，因此应该结合起来研究。
overt
adj. public； not secret 公开的，公然的，明显的
overt market 公开市场/overt hostility 公开的敌对/an overt sign 明显的迹象
According to the United States Constitution，a person must commit an overt act before he may be tried for treason.
根据美国宪法，一个人在受叛国罪的审判之前，必须要有公然的行为。
overthrow
vt. to throw over； overturn打倒，推翻，颠覆 n. an instance of overthrowing， esp. one that results in downfall or destruction 推翻，打倒，扔得过远得球
Fascism had lawlessly overthrown the democratic government of this country.
法西斯主义已经非法地推翻了这个国家的民主政府。
overwhelm
vt. to surge over and submerge； engulf； to defeat completely and decisively 淹没，覆没，受打击，制服，压倒
be overwhelmed by grief 伤心已极/be overwhelmed with horror 吓得魂不附体/be overwhelmed with excitement 极为兴奋
I was overwhelmed by their kindness and moved to tears.
我被他们的好心好意弄得非常激动，感动得流下了泪。
oxide
n. (chemistry 化）compound of oxygen and one other substance 氧化物
iron oxide 氧化铁 /oxide of tin 氧化锡