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B2 adjective /ˈɒnɡəʊɪŋ/

ongoing

进行中
Meaning
continuing; still in progress
Example
The ongoing project will finish next month.
进行中的项目将在下个月完成。
C2 noun /əˈblɪkwɪti/

obliquity

歪曲
Meaning
Deviation from moral or usual conduct; indirectness or lack of straightforwardness.
Example
The politician was criticized for the obliquity of his answers.
那位政治家因其回答的歪曲性而受到批评。
C2 adjective /ɒˈstɛnsɪv/

ostensive

显性
Meaning
clearly demonstrative or pointing out; explicitly shown
Example
The teacher gave an ostensive example to clarify the concept.
老师举了一个显性的例子来阐明概念。
B2 noun /ˈɒs.trɪtʃ/

Ostrich

鸵鸟
Meaning
a large flightless bird native to Africa with long legs and neck
Example
The ostrich is the world's largest bird.
鸵鸟是世界上最大的鸟。
C1 adverb /ˈɒp.tɪ.məl.i/

optimally

最优地
Meaning
In the most effective or efficient way possible.
Example
Tasks should be allocated optimally for maximum output.
任务应当最优地分配，以实现最大产出。
C2 noun /oʊˈbeɪsəns/

obeisance

敬礼
Meaning
A gesture of respect such as a bow or curtsy.
Example
They bowed in obeisance to the king.
他们向国王行了敬礼。
C1 noun /ˈaʊtˌɡroʊθ/

outgrowth

衍生物
Meaning
something that grows out of something else; a natural development or result
Example
The new policy was an outgrowth of years of debate.
新政策是多年辩论的衍生物。
C1 noun /ˈoʊvərˌtoʊn/

overtone

微妙的含义
Meaning
A subtle quality, implication, or additional meaning beyond the obvious.
Example
His speech had political overtones that were hard to ignore.
他的演讲具有政治性含义，难以忽视。
B2 noun ɔːˈɡæn.ɪk fuːdz

organic foods

有机食品
Meaning
Food produced without the use of chemicals such as artificial pesticides, fertilizers, or other artificial agents.
Example
Organic foods are healthier than processed foods.
有机食品比加工食品更健康。
B2 adjective /ˈɒp.ʃən.əl/

Optional

可选的
Meaning
not compulsory; left to choice
Example
Wearing a tie is optional for this event.
穿领带是这个活动的可选项。
C2 adjective /ˈoʊ.vɔɪd/

ovoid

卵形
Meaning
egg-shaped; resembling an oval or ellipse
Example
The artist painted an ovoid shape in the center of the canvas.
艺术家在画布中心画了一个卵形的形状。
A1 adjective/adverb /ˈoʊnli/

only

唯一
Meaning
without others; solely
Example
He is the only person who knows the secret.
他是唯一知道这个秘密的人。
C1 verb /ˌoʊvərˈruːl/

overrule

驳回
Meaning
to reject or disallow by exercising one's superior authority; to override a decision
Example
The judge overruled the objection from the defense attorney.
法官驳回了辩护律师的反对。
C1 verb /ˌaʊtˈstrɪp/

outstrip

超越
Meaning
To go faster or do better than someone or something; to surpass.
Example
The company outstripped its competitors in sales last year.
公司在去年超越了它的竞争对手。
C2 adjective /ˈoʊ.kən/

oaken

由橡木制成
Meaning
made of or resembling oak wood
Example
The villagers gathered around the oaken table in the hall.
村民们围着大厅里的橡木桌子聚集在一起。
B2 noun ˈɔː.bɪt

orbit

轨道
Meaning
The curved path of a celestial object around a star, planet, or moon.
Example
The satellite maintains its orbit around Earth.
卫星保持它绕地球的轨道。
B2 noun /ˈaʊtlet/

outlet

出口
Meaning
a means by which something is released, expressed, or distributed
Example
Art is a great outlet for emotions.
艺术是情感的一个极好的出口。
B2 adjective /əˈpəʊzd/

opposed

反对的
Meaning
being against or in disagreement with something
Example
She is strongly opposed to animal testing.
她坚决反对动物实验。
B2 noun /ˈaʊtskɜːrts/

outskirts

城市边缘
Meaning
The outer parts of a town or city, away from the center.
Example
They moved to the outskirts of the city for a quieter life.
他们为了更安静的生活搬到了城市的边缘。
B2 adjective /ˌɔːɡənaɪˈzeɪʃənəl/

organizational

组织性的
Meaning
relating to the structure or arrangement of a company or group
Example
He works on improving the organizational structure of the company.
他在改善公司的组织结构方面工作。
C1 noun /ˈɒn.slɔːt/

onslaught

猛攻
Meaning
A fierce or destructive attack.
Example
The village faced an onslaught of enemy forces.
这个村庄面临敌军的猛烈进攻。
B2 verb /əbˈteɪn/

obtain

获得
Meaning
to get or acquire something
Example
You need to obtain a visa before traveling abroad.
你需要在出国前获得签证。
A2 preposition /ˈɒntu/

onto

在…上
Meaning
moving to a position on the surface of something
Example
She jumped onto the table to get the book.
她跳到桌子上去拿书。
B2 noun /ˌɑb.zɚˈveɪ.ʃən/

Observation

观察
Meaning
the action of watching something carefully; a comment or remark
Example
The scientist made careful observations of the experiment.
科学家仔细观察了实验。
C1 verb ˈɔː.kɪ.streɪ.tɪd

orchestrated

精心策划
Meaning
Planned or coordinated carefully and deliberately.
Example
The attacks were orchestrated with precision.
袭击被精确地策划了。
B2 noun ˈɒksɪdʒən prəˈdʌkʃən

oxygen production

氧气生产
Meaning
The process of generating oxygen through photosynthesis or other means.
Example
Plants are vital for oxygen production and the maintenance of life.
植物对于氧气生产和维持生命至关重要。
B2 noun /əbˈzɜːvər/

observer

观察者
Meaning
a person who watches or notices something
Example
The observer took notes during the meeting.
观察者在会议期间做了笔记。
A2 noun /əˈlɪmpɪks/

olympics

奥林匹克运动会
Meaning
an international sports competition held every four years with athletes from many countries
Example
The Olympics bring athletes from all over the world together.
奥林匹克运动会将全世界的运动员聚集在一起。
B2 noun /ˈaʊt.saɪ.dər/

Out-sider

局外人
Meaning
a person who does not belong to a particular group; someone not accepted by a group
Example
As an outsider, he found it difficult to understand their traditions.
作为外人，他发现很难理解他们的传统。
C2 noun /ˈɒfərtɔːri/

offertory

奉献
Meaning
The part of a religious service when offerings are collected; the offering itself.
Example
The offertory was taken during the Sunday service.
奉献在星期日的礼拜期间收集。
A2 adjective /ˈaʊtdɔːr/

outdoor

户外
Meaning
situated, existing, or done outside a building
Example
We planned an outdoor picnic for the weekend.
我们计划了一个户外野餐，周末进行。
C1 noun /ˈɒstrəsɪzəm/

ostracism

排斥
Meaning
The act of excluding someone from a group or society.
Example
The student faced ostracism after breaking the rules.
学生在违反规则后遭受了排斥。
B2 noun /ˈaʊtˌsɛt/

outset

开始
Meaning
the beginning or start of something
Example
From the outset, the project seemed ambitious but achievable.
从一开始，项目看起来雄心勃勃但可以实现。
C1 noun ˌɒb.səˈlɛs.əns

obsolescence

淘汰
Meaning
The process of becoming obsolete or outdated and no longer used.
Example
The rapid advancement of technology leads to the obsolescence of old devices.
科技的快速发展导致旧设备的淘汰。
C1 adjective /ˌaʊtˈspoʊkən/

Outspoken

直言不讳
Meaning
frank; speaking directly
Example
She is known for being outspoken about social issues.
她因直言不讳地谈论社会问题而闻名。
A2 noun /ˈɒbdʒɪkt/

object

物体
Meaning
a thing that can be seen and touched
Example
The table is an object in the room.
桌子是房间里的一个物体。
B1 verb /ˈɒpəreɪt/

operate

操作
Meaning
to function; to control or manage; to perform surgery
Example
The surgeon will operate on the patient tomorrow.
外科医生明天将为病人做手术。
C1 adjective /ˈaʊt.kɑːst/

Outcast

被排斥的人
Meaning
rejected by society; excluded person
Example
He felt like an outcast in his new school.
他在新学校里感觉自己像一个被排斥的人。
C2 verb /ˈɔːreɪt/

orate

演讲
Meaning
To speak in a formal, often pompous manner
Example
He began to orate at the ceremony.
他在仪式上开始演讲。
C1 noun /oʊθ/

Oath

誓言
Meaning
a solemn promise or declaration; a sworn statement
Example
The doctor took an oath to help patients.
医生宣誓帮助病人。
C1 adjective ˈɒk.sɪ.də.tɪv

oxidative

与氧化相关
Meaning
Related to or caused by oxidation, especially cellular damage from free radicals.
Example
Excess stress can lead to oxidative damage in cells.
过度的压力可能导致细胞中的氧化损伤。
B2 noun /ˌɒpəˈzɪʃən/

opposition

反对
Meaning
the action of opposing or resisting something
Example
The opposition to the new law was strong.
对新法律的反对很强烈。
C2 verb /aʊtˈraɪd/

outride

超越
Meaning
to ride faster, farther, or better than someone else
Example
The young rider managed to outride his competitors in the race.
年轻的骑手在比赛中成功超越了他的竞争对手。
C1 adjective /ˌɔːrnəˈmɛntl/

ornamental

装饰性的
Meaning
Serving as decoration; decorative rather than functional.
Example
The garden was filled with ornamental plants.
花园里满是装饰性的植物。
C1 noun /ˈəʊ.nəs/

onus

责任
Meaning
A duty or responsibility, especially a heavy one.
Example
The onus is on the government to provide relief to the victims.
政府有责任向受害者提供援助。
B2 noun /ˈɔːɡən/

organ

器官
Meaning
a part of the body that performs a specific function
Example
The heart is an important organ in the human body.
心脏是人体重要的器官。
B2 noun /ˈɑp.tə.mɪst/

Optimist

乐观主义者
Meaning
a person who tends to be hopeful and confident about the future; someone who sees the good side of things
Example
As an optimist, she always believed things would improve.
作为乐观主义者，她一直相信事情会变得更好。
C1 noun /ˌɒbstəˈtrɪʃən/

obstetrician

产科医生
Meaning
A doctor specializing in pregnancy, childbirth, and women's reproductive health.
Example
The obstetrician monitored the mother’s health throughout the pregnancy.
产科医生在整个怀孕过程中监测了母亲的健康。
C1 adjective /əbˈstrʌk.tɪv/

Obstructive

阻碍性的
Meaning
deliberately creating difficulties or preventing progress; hindering or blocking something
Example
The obstructive policies hindered economic growth.
这些阻碍性的政策阻碍了经济增长。
C2 noun /ˈɒbsɪkwi/

obsequy

葬礼仪式
Meaning
A funeral rite, usually used in plural form obsequies.
Example
The village gathered for the obsequy of their beloved teacher.
村庄聚集在一起，参加他们心爱的老师的葬礼。
C1 verb /əbˈsɛs/

obsess

Meaning
To preoccupy or fill the mind of someone continually and to an excessive degree.
Example
She tends to obsess over small details.
C1 verb /ˌoʊvərˈʃædoʊ/

overshadow

掩盖
Meaning
to appear more important or significant than something else, reducing its impact
Example
The scandal overshadowed his achievements.
丑闻掩盖了他的成就。
B2 noun /ˌɒb.zəˈveɪ.ʃənz/

observations

观察
Meaning
The action or process of observing something carefully.
Example
Observations of distant galaxies provide new insights.
对遥远星系的观察提供了新的见解。
C1 verb /ˌaʊtˈstrɛtʃ/

outstretch

伸展
Meaning
To extend or stretch something outward.
Example
He outstretched his hand to help her up.
他伸出手来帮助她站起来。
B2 adjective + noun ˈɒptɪməl ˈtempərətʃər

optimal temperature

最佳温度
Meaning
The best or most favorable temperature for a particular purpose
Example
Winter provides optimal temperature for farming.
冬天提供了农业的最佳温度。
C2 noun /ˈɔːrzmən/

Oarsman

划船者
Meaning
a person who rows a boat, especially as a member of a racing crew
Example
The experienced oarsman rowed the boat across the river.
经验丰富的划船者划船过了河。
C1 noun /əˈkɜr.əns/

Occurrence

事件
Meaning
an instance or event of something happening; the fact of occurring
Example
The occurrence of earthquakes is common in this region.
地震的发生在这个地区很常见。
C2 noun /ˌɒstɛnˈteɪʃən/

ostentation

炫耀
Meaning
excessive display of wealth or knowledge intended to attract admiration or envy
Example
The billionaire’s party was full of ostentation and luxury.
亿万富翁的派对充满了炫耀和奢华。
C1 adjective /əˈblɪɡ.ə.tɔː.ri/

obligatory

强制的
Meaning
Required by a legal, moral, or other rule; compulsory.
Example
Wearing a seatbelt is obligatory in most countries.
在大多数国家，系安全带是强制的。
B1 noun /ˈɒbstəkəlz/

obstacles

障碍
Meaning
Things that block one's way or prevent or hinder progress.
Example
Obstacles in life can often lead to valuable lessons.
生活中的障碍常常导致宝贵的教训。
C2 verb /ˈɑːbvieɪt/

obviate

消除
Meaning
To remove a need or difficulty; to prevent or avoid something.
Example
This new system obviates the need for manual data entry.
这个新系统消除了手动输入数据的需要。
B1 noun əbˈdʒek.tɪv

objective

目标
Meaning
A thing aimed at or sought; a goal.
Example
The main objective is to test sustainability.
主要目标是测试可持续性。
A2 adjective /əˈlɪmpɪk/

olympic

奥林匹克
Meaning
related to the Olympic Games, a major international sporting event
Example
She trained hard to compete in the Olympic Games.
她努力训练，为了参加奥林匹克运动会。
C2 verb /ˈɒsɪfaɪ/

ossify

骨化
Meaning
to turn into bone or become rigid and inflexible
Example
With age, some tissues tend to ossify.
随着年龄的增长，一些组织会变得僵硬。
B2 adverb /ˈaʊtraɪt/

Outright

直接; 完全; 毫不保留
Meaning
completely; directly; without reservation or concealment
Example
She rejected the proposal outright.
她直接拒绝了那个提案。
C1 noun /ˈɔːrdɪnəns/

ordinance

法令
Meaning
An authoritative rule, law, or decree issued by a city, town, or authority.
Example
The city council passed an ordinance banning smoking in public parks.
市议会通过了一项法令，禁止在公共公园内吸烟。
C2 adjective /ˈɑːsɪˌfaɪd/

ossified

变成骨头，僵硬
Meaning
Turned into bone or become rigid; unwilling to change.
Example
The company had an ossified management structure that resisted innovation.
该公司有一个僵化的管理结构，抵制创新。
C2 adjective /ˈoʊdiəs/

odious

可憎的
Meaning
extremely unpleasant or repulsive
Example
The dictator was remembered for his odious crimes.
这位独裁者因他可憎的罪行而被记住。
C2 noun /ˈoʊ.kəm/

oakum

旧绳纤维
Meaning
loose fibers obtained by untwisting old ropes, used for caulking ships
Example
The shipbuilders used oakum to seal the gaps in the wooden planks.
造船工人使用欧卡姆来密封木板之间的缝隙。
C1 adjective /əˈprɛs.ɪv/

Oppressive

压迫的
Meaning
Harsh and authoritarian; overwhelming; causing distress; tyrannical;
Example
The oppressive heat made it difficult to work outside during the summer.
压迫性的热浪使得夏天在外工作变得很困难。
C1 noun /ˈɔr.ə.kəl/

Oracle

神谕
Meaning
a person regarded as a source of wise counsel; in ancient times, a priest or priestess acting as a medium
Example
The ancient Greeks consulted the oracle at Delphi.
古希腊人曾在德尔菲咨询神谕。
C1 verb ˈɔːr.kɪ.streɪt

orchestrate

协调
Meaning
To plan or coordinate the elements of (a situation) to produce a desired effect, especially surreptitiously.
Example
He skillfully orchestrated the entire event.
他巧妙地策划了整个活动。
C1 verb /əˈprɛs/

oppress

压迫
Meaning
to keep someone down by harsh and unfair use of authority; to suppress
Example
The dictator oppressed the people for decades.
独裁者压迫人民数十年。
A2 pronoun /aʊərˈsɛlvz/

ourselves

我们自己
Meaning
used by the speaker to refer to themselves and one or more others as the object of the verb
Example
We should help ourselves before helping others.
我们应该在帮助他人之前先帮助自己。
C1 noun /ˈɒktɪv/

octave

Meaning
A series of eight musical notes, or the interval between one musical pitch and another with double its frequency.
Example
The singer's voice could easily reach the higher octave.
C2 noun /əbˈstɛtrɪks/

obstetrics

产科
Meaning
The branch of medicine dealing with childbirth and care of women giving birth.
Example
She is studying obstetrics to become a specialist in childbirth.
她正在学习产科，想成为一名分娩专家。
C1 adjective /ɔːˈneɪt/

ornate

华丽的
Meaning
elaborately or highly decorated
Example
The palace hall was filled with ornate furniture and paintings.
宫殿的大厅里充满了华丽的家具和画作。
C2 noun /ɔːˈreɪʃən/

oration

演讲
Meaning
A formal speech, especially one given on a ceremonial occasion
Example
The president delivered an inspiring oration.
总统发表了鼓舞人心的演讲。
B1 noun /əˈkeɪ.ʒən/

Occasion

场合; 特殊事件
Meaning
a particular time or instance of an event; a special celebration
Example
Their wedding was a joyous occasion.
他们的婚礼是一个喜庆的场合。
C2 adjective /əˈrækjələr/

oracular

神谕的
Meaning
Resembling an oracle; giving wise, mysterious, or prophetic statements
Example
Her oracular words left the audience deep in thought.
她的神谕般的话让观众陷入了深思。
B2 noun /ɑːks/

Ox

牛
Meaning
a large strong animal used for pulling heavy loads or plowing fields
Example
The farmer used an ox to plow the field.
农民用牛耕地。
C1 verb /ˌaʊtˈduː/

outdo

超越
Meaning
To do better than someone else; to surpass.
Example
She always tries to outdo her classmates in exams.
她总是尽力在考试中超越她的同学。
C1 noun ˌɒp.tɪ.maɪˈzeɪ.ʃən

optimization

优化
Meaning
Improving processes to increase performance and efficiency.
Example
SEO optimization helps websites rank higher on search engines.
SEO优化帮助网站在搜索引擎中排名更高。
C2 noun /oʊf/

Oaf

笨拙、愚蠢或麻木的人
Meaning
a clumsy, stupid, or insensitive person
Example
Don't be such an oaf - handle the dishes carefully!
不要做那种笨蛋 – 小心洗碗！
B1 adjective /ˌoʊvərˈsiːz/

overseas

海外
Meaning
in or to a foreign country across the sea
Example
He went overseas for higher education.
他去海外深造。
C1 adjective /oʊˈbiːs/

obese

肥胖
Meaning
Extremely overweight; having an excessive amount of body fat.
Example
The doctor advised the obese patient to adopt a healthier lifestyle.
医生建议肥胖的病人采取更健康的生活方式。
C2 adjective /ˈɒsiəs/

osseous

骨质的
Meaning
consisting of or turned into bone; bony
Example
The fossil showed osseous structures of the ancient creature.
化石展示了古老生物的骨质结构。
C1 noun /ˈɒfʃuːt/

offshoot

分支
Meaning
A branch or result that develops from something larger or more important.
Example
The startup was an offshoot of a major tech company.
这家初创公司是一个大型科技公司分支。
B1 noun ˌɔː.ɡən.aɪˈzeɪ.ʃənz

organizations

组织
Meaning
Organized groups of people with a particular purpose
Example
Organizations play a key role in policymaking.
组织在政策制定中发挥着重要作用。
C1 noun /ˈaʊtˌkraɪ/

outcry

抗议
Meaning
A strong expression of public anger or disapproval.
Example
The decision sparked an outcry among the citizens.
这个决定在市民中引发了抗议。
C1 noun /ˈɒptɪks/

optics

光学
Meaning
The branch of physics dealing with light and vision.
Example
She studied optics to understand how lenses work.
她学习了光学，以了解镜头是如何工作的。
C1 noun /ˌɑːk.sɪˈmɔːr.ɒn/

oxymoron

矛盾修饰法
Meaning
a figure of speech where two contradictory terms are combined
Example
The phrase 'deafening silence' is a classic oxymoron.
短语 '震耳欲聋的寂静' 是一个经典的矛盾修饰法。
C2 verb /əˈkluːd/

occlude

堵塞
Meaning
To block or close up an opening or passage.
Example
The pipe was occluded by mineral deposits.
管道因矿物沉积物而被堵塞。
C2 adjective /əˈprəʊ.bri.əs/

opprobrious

侮辱性的
Meaning
Expressing strong criticism or scorn.
Example
He made opprobrious remarks about his opponent.
他对对手做出了侮辱性评论。
C1 noun /ˈɑd.ɪ.ti/

Oddity

奇异现象
Meaning
something that is strange or unusual; a peculiar trait
Example
His habit of sleeping standing up was considered an oddity.
他站着睡觉的习惯被视为一种奇异现象。
B2 adjective ɔːrˈɡæn.ɪk

organic

有机的
Meaning
Produced or involving production without the use of chemical fertilizers, pesticides, or other artificial agents.
Example
Organic farming improves soil health and reduces pollution.
有机农业改善土壤健康并减少污染。
C1 adjective /əˈblaɪdʒɪŋ/

obliging

乐于助人
Meaning
Willing to help or do favors; accommodating.
Example
The staff at the hotel were very obliging and friendly.
酒店的工作人员非常乐于助人且友好。
B2 verb /ˌoʊvərˈkʌm/

overcome

克服
Meaning
To succeed in dealing with a problem or difficulty.
Example
You can overcome procrastination with planning.
你可以通过计划来克服拖延症。
B2 verb /ɒpt/

opt

选择
Meaning
to choose or decide to do something instead of something else
Example
Many students opt to study abroad for better opportunities.
许多学生选择出国留学以获得更好的机会。
C1 verb /ˈɔːstrəˌsaɪz/

ostracize

排斥
Meaning
to exclude someone from a group or society; to banish or shun
Example
After the scandal, he was ostracized by his former colleagues.
丑闻发生后，他被前同事排斥。
C2 adjective /ˈɒfɪʃ/

offish

冷淡
Meaning
Unfriendly, distant, or reserved in manner.
Example
He seemed offish at the party and avoided most conversations.
他在派对上显得很冷淡，避开了大多数谈话。
C1 adjective /əbˈnɒkʃəs/

Obnoxious

令人讨厌的；惹人厌的；极其讨厌的
Meaning
extremely unpleasant; offensive; annoying
Example
His obnoxious behavior at the party annoyed everyone.
他在聚会上的令人讨厌的举止惹恼了在场的每一个人。
B2 adverb /ˈoʊpənli/

Openly

公开地; 公共地
Meaning
in a frank and honest way; without concealment; publicly
Example
She spoke openly about her struggles with mental health.
她公开谈论了自己在心理健康方面的困难。
C2 adjective /ˈɔːrəˌtʌnd/

orotund

深沉而清晰的声音
Meaning
full, rich, and clear in sound; pompous in style
Example
The actor's orotund voice filled the theater.
演员的深沉声音充满了剧院。
B2 noun /ˈɔːkɪstrə/

orchestra

管弦乐队
Meaning
a large group of musicians playing different instruments together
Example
The orchestra performed beautifully at the concert.
管弦乐队在音乐会上演奏得非常出色。
C2 noun /ˌɔːrnɪˈθɒlədʒɪst/

ornithologist

鸟类学家
Meaning
a scientist who studies birds
Example
The ornithologist spent years studying migratory birds.
这位鸟类学家花了多年时间研究迁徙鸟类。
B2 verb /ˈɒkjʊpaɪ/

occupy

占据
Meaning
to take up space or time; to live or work in a place
Example
The new family will occupy the house next month.
新家庭将于下个月入住这所房子。
C1 adjective /aʊtˈmoʊdɪd/

outmoded

过时的
Meaning
No longer in fashion or useful; outdated.
Example
That old computer is completely outmoded.
那台旧电脑完全过时了。
A2 noun /ˈɒf.ɪs/

office

办公室
Meaning
a room or building where people work, usually at desks
Example
She left the office early to attend a family event.
她提前离开办公室去参加家庭活动。
C2 adjective /əbˈtruːsɪv/

obtrusive

干扰的
Meaning
noticeable in an unpleasant or unwelcome way; intrusive
Example
The advertisement was so obtrusive that it ruined the user’s experience.
广告如此显眼，以至于破坏了用户体验。
C2 noun /ɑːlˈfækʃən/

olfaction

嗅觉
Meaning
The sense of smell; the process of detecting and perceiving odors.
Example
Dogs have a highly developed sense of olfaction.
狗的嗅觉非常发达。
A2 noun /ˈoʊ.ʃən/

ocean

海洋
Meaning
A very large expanse of sea, especially the main areas of sea between continents.
Example
The ocean covers more than 70% of the Earth's surface.
海洋覆盖了地球表面超过70%。
B2 noun, verb /ˈaʊtlɔː/

outlaw

Meaning
as a noun: a person who breaks the law and lives outside its protection; as a verb: to make something illegal
Example
The government decided to outlaw the harmful practice.
C2 adjective /əbˈstrɛpərəs/

obstreperous

喧闹且难以控制
Meaning
Noisy and difficult to control.
Example
The obstreperous students disrupted the class.
那些喧闹的学生打乱了课堂。
C2 adjective /ˈoʊ.pən ˈhɑrt.ɪd/

Open-hearted

开放的心; 慷慨和真诚; 热情接纳;
Meaning
Kind and generous; sincere and honest; warmly receptive;
Example
She welcomed the strangers with an open-hearted smile and invited them for dinner.
她以开放的微笑欢迎陌生人，并邀请他们共进晚餐。
B2 verb /ˌoʊvərˈiːt/

overeat

幸福
Meaning
To eat more food than the body needs.
Example
She tends to overeat when she is stressed.
她在收到奖项时无法掩饰自己的幸福。
C1 noun /ɒpˈtɒmɪtrɪst/

optometrist

眼科验光师
Meaning
A healthcare professional who examines eyes and prescribes corrective lenses.
Example
The optometrist prescribed new glasses for her.
眼科验光师为她开了新的眼镜。
C1 noun /oʊˈmɪʃ.ən/

Omission

省略; 排除
Meaning
the action of excluding or leaving out someone or something; a failure to include
Example
The omission of his name from the list was intentional.
从列表中省略他的名字是故意的。
B2 verb /ˌoʊvərˈteɪk/

overtake

超过
Meaning
to catch up with and pass someone or something; to surpass
Example
The runner managed to overtake his competitor in the final lap.
跑步者在最后一圈超过了他的竞争对手。
C2 verb /ˈɑːskjʊleɪt/

osculate

亲吻
Meaning
To kiss.
Example
They osculated under the mistletoe during the party.
他们在派对上在槲寄生下接吻。
C1 adjective /ɒˈstɛnsəbl/

ostensible

表面上
Meaning
stated or appearing to be true, but not necessarily so
Example
His ostensible reason for leaving was illness, but many doubted it.
他离开的表面上原因是生病，但许多人对此表示怀疑。