overcrowding
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B2 noun /ˌoʊ.vɚˈkraʊ.dɪŋ/

overcrowding

过度拥挤
Meaning
Excessive crowd or packed condition, having more people or vehicles in a place than the approved capacity.
Example
The subway system suffers from severe overcrowding during peak hours.
地铁系统在高峰时段面临严重的过度拥挤。
C2 noun /ˈoʊ.vər.let/

Overlet

床垫
Meaning
a thin mattress or pad placed over a bed for additional comfort
Example
The overlet makes the bed more comfortable to sleep on.
欧弗雷特使床铺更适合睡觉。
C2 noun /ɔːrˈθɑːɡrəfi/

orthography

拼写法
Meaning
The conventional spelling system of a language.
Example
English orthography can be confusing for learners.
英语的拼写法对学习者来说可能是令人困惑的。
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 /ˈɒfərɪŋ/

offering

提供
Meaning
something that is given, especially as a gift or contribution
Example
The company’s latest offering is an eco-friendly car.
公司的最新产品是一款环保汽车。
C1 noun /ˈɔr.ə.tər/

Orator

演说家
Meaning
a public speaker, especially one who is eloquent or skilled in speaking
Example
The famous orator delivered an inspiring speech.
这位著名的演说家发表了一场鼓舞人心的演讲。
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。
A2 verb /ˈɔːfər/

offer

提供
Meaning
to present something for acceptance or rejection; to propose
Example
She offered to help with the project.
她提出帮助这个项目。
C2 verb /ˈɑːblɪˌɡeɪt/

obligate

强迫
Meaning
to bind legally or morally; to compel someone to do something
Example
The contract obligates the company to provide timely service.
合同使公司有义务提供及时服务。
B2 noun /ɔːˈræŋ.ʊˌtæŋ/

Orang-Outang

猩猩
Meaning
a large arboreal ape with long reddish hair, long arms, and hooked hands and feet, native to Borneo and Sumatra
Example
The orangutan swings gracefully through the forest canopy.
猩猩优雅地穿越森林的树冠。
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The process of becoming obsolete or outdated and no longer used.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。
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。
C1 noun /ˈoʊ.vər spɪl/

Over-spill

溢出
Meaning
the overflow of liquid from a container; excess that cannot be contained
Example
The overspill from the river flooded nearby farms.
河水溢出导致附近的农田被淹没。
B2 noun /ˌaʊtˈsaɪdə(r)/

outsider

局外人
Meaning
a person who is not accepted as a member of a particular group or community
Example
As a new student, she often felt like an outsider at school.
作为新生，她常常觉得自己在学校是个局外人。
C1 noun əˈblɪv.i.ən

oblivion

遗忘, 灭绝, 消失
Meaning
The state of being unaware or unconscious of what is happening; complete forgetfulness.
Example
His name faded into oblivion over time.
随着时间的推移，他的名字渐渐消失在遗忘中。
B2 noun /ˈɔːɡənɪzəm/

organism

有机体
Meaning
a living thing that has an organized structure and can grow and reproduce
Example
Every organism needs water to survive.
每个有机体都需要水才能生存。
B2 adjective /əˈfen.sɪv/

Offensive

冒犯的; 侮辱的; 攻击性的
Meaning
causing displeasure or resentment; insulting; aggressive
Example
His offensive remarks hurt everyone's feelings.
他的冒犯言论伤害了每个人的感情。
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。
C1 noun /ˈɒf.sprɪŋ/

offspring

后代
Meaning
a person's child or children; an animal's young
Example
The bird carefully fed its offspring.
那只鸟小心地喂养了它的后代。
C1 adjective /ˈəʊnərəs/

onerous

繁重
Meaning
involving a great deal of effort, difficulty, or burden
Example
Fulfilling the contract proved to be an onerous task for the company.
履行合同对公司来说是一项繁重的任务。
B2 noun ˈoʊzoʊn dɪˈpliʃən

ozone depletion

臭氧消耗
Meaning
The reduction in the amount of ozone in the Earth's stratosphere, leading to increased UV radiation.
Example
Ozone depletion increases UV radiation.
臭氧消耗增加了紫外线辐射。
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。
B2 adjective /aʊtˈstændɪŋ/

outstanding

杰出
Meaning
extremely good or impressive; not yet resolved or paid
Example
She received an award for her outstanding performance.
她因出色的表现获得了奖项。
B2 noun /əˈfɛns/

offense

犯罪
Meaning
an illegal act; a crime
Example
The offense was committed in broad daylight.
这个犯罪是在白天犯下的。
B2 noun /ˈaʊtbɜːrst/

outburst

情感或活动的突然爆发
Meaning
a sudden release of strong emotion or activity
Example
She had an angry outburst during the meeting.
她在会议期间突然发火。
C2 adjective /ˌoʊpəˈlɛsənt/

opalescent

欧泊色的
Meaning
showing or reflecting a milky, iridescent light like an opal
Example
The opalescent sky glowed with shades of pink and blue.
欧泊色的天空闪烁着粉色和蓝色的色调。
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。
C2 noun /ɒmˈnɪpətəns/

omnipotence

全能
Meaning
The quality of having unlimited power or authority.
Example
Many religions describe God’s omnipotence as absolute.
许多宗教将上帝的全能描述为绝对的。
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。
B2 noun /oʊk/

oak

橡树
Meaning
a large tree that produces acorns and has strong, hard wood
Example
The old oak tree provided shade for the entire yard.
那棵老橡树为整个院子提供了阴凉。
B2 noun /ˈɒt.ər/

Otter

水獺
Meaning
a mammal with webbed feet that lives near water and feeds on fish
Example
The playful otter swam gracefully in the river.
顽皮的水獺优雅地在河里游泳。
C1 noun /əˈfen.dər/

Offender

罪犯; 违法者
Meaning
a person who commits an illegal act; someone who breaks the law
Example
The young offender was sentenced to community service.
那个年轻的罪犯被判社区服务。
B2 noun /wʌn θɜːd/

one-third

三分之一
Meaning
one part of something that is divided into three equal parts
Example
One-third of the class was absent today.
班级的三分之一今天缺席。
C1 adjective əʊˈpeɪk

opaque

不透明, 难以理解
Meaning
Not able to be seen through; not transparent; difficult to understand.
Example
The glass was too opaque to see through.
玻璃太不透明，无法看透。
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。
A1 verb, adjective /oʊn/

own

拥有
Meaning
to possess something; belonging to oneself
Example
She owns a beautiful house in the city.
她拥有一座漂亮的房子。
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。
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 /ˌəʊvərɪksˌplɔɪˈteɪʃən/

overexploitation

过度开发
Meaning
The unsustainable use of natural resources at a rate that exceeds their ability to regenerate, leading to depletion and environmental degradation.
Example
Overexploitation of natural resources leads to environmental degradation.
过度开发自然资源会导致环境退化。
B2 noun /ˈoʊtˌmiːl/

oatmeal

燕麦粥
Meaning
A type of porridge made from ground oats, often eaten for breakfast.
Example
She eats a bowl of oatmeal every morning for breakfast.
她每天早晨吃一碗燕麦粥当早餐。
C1 verb /ˌoʊvərˈpaʊər/

overpower

征服
Meaning
To defeat or gain control over someone or something by using greater strength or force.
Example
The soldiers managed to overpower the enemy forces.
士兵们成功压倒了敌军。
C2 noun /ˈoʊpiət/

opiate

Meaning
a drug containing opium or its derivatives, used to relieve pain or cause sleep
Example
The doctor prescribed an opiate to relieve the patient's pain.
B1 adjective /ˌoʊld ˈfæʃənd/

old-fashioned

过时的
Meaning
not modern; belonging to an earlier time
Example
He still wears an old-fashioned hat.
他仍然戴着一顶过时的帽子。
C1 adjective əˈblɪv.i.əs

oblivious

无意识的
Meaning
Being completely unaware of surrounding events.
Example
He was oblivious to the noise around him while reading.
他在阅读时完全没有意识到周围的噪音。
C1 adjective /ˌəʊvərˈstɪmjʊˌleɪtɪd/

overstimulated

过度刺激的
Meaning
Excessively excited or aroused, overwhelmed by too much stimulus.
Example
Overstimulated minds can lead to burnout and decreased productivity.
过度刺激的头脑可能导致倦怠和生产力下降。
C1 noun /ˌɒk.sɪ.dʒɪˈneɪ.ʃən/

oxygenation

供氧或氧气治疗
Meaning
The process of supplying or treating with oxygen.
Example
Deep breathing exercises improve oxygenation of the body.
深呼吸练习有助于改善身体的供氧。
A2 verb /oʊˈbeɪ/

obey

服从
Meaning
to follow orders or instructions; to comply with rules
Example
Children should obey their parents and teachers.
孩子们应该服从父母和老师的命令。
B2 verb /ˌoʊvərˈtɜrn/

overturn

推翻 / 取消裁决
Meaning
to turn something upside down or to reverse a decision or judgment
Example
The court decided to overturn the previous ruling.
法院决定推翻先前的裁决。
C2 noun /ˈɑːbəlɪsk/

obelisk

方尖碑
Meaning
A tall, four-sided, narrow tapering monument with a pyramid-shaped top.
Example
The ancient Egyptians built obelisks to honor their gods.
古埃及人建造了方尖碑来纪念他们的神。
B2 noun/verb /ˈoʊvərˌdoʊs/

overdose

过量服药
Meaning
An excessive and dangerous amount of a drug; to take too much of a substance.
Example
He was rushed to the hospital after a drug overdose.
他因毒品过量被送进了医院。
A2 adjective/adverb /ˈɒnˌlaɪn/

online

在线
Meaning
connected to or available through the internet
Example
I prefer shopping online rather than going to stores.
我更喜欢网上购物，而不是去商店。
A1 pronoun, noun, adjective /wʌn/

one

一
Meaning
the number equivalent to the sum of zero and one; a single person or thing
Example
Only one student answered the question.
只有一个学生回答了问题。
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。
A1 pronoun /aʊər/

our

我们的
Meaning
belonging to or associated with the speaker and one or more other people
Example
This is our house.
这是我们的房子。
B2 adjective ˌɒp.ərˈeɪ.ʃən.əl

operational

操作的
Meaning
In working order; ready for use.
Example
The space project will be operational by 2025.
太空项目将在2025年投入使用。
C2 adjective /ˈɒpjʊlənt/

opulent

奢华的
Meaning
Ostentatiously rich, luxurious, or lavish.
Example
They hosted an opulent wedding with gold decorations.
他们举办了一场奢华的婚礼，装饰有金色装饰品。
B2 noun /ˈaʊtɪŋ/

outing

短途旅行
Meaning
a short trip or excursion, often for leisure or enjoyment
Example
They had a lovely outing at the beach last weekend.
他们上周末在海滩上度过了一个美好的短途旅行。
B2 verb əbˈzɜːrvd

observed

庆祝
Meaning
To celebrate or keep a religious or other festival.
Example
The day is observed annually to raise awareness.
这一天每年庆祝，以提高意识。
B1 noun /ˌɒpəˈreɪʃən/

operation

手术
Meaning
an act or process of functioning or operating
Example
The hospital performed a successful operation.
医院进行了成功的手术。
B1 noun /əˈpɪn.jən/

Opinion

意见
Meaning
a view or judgment formed about something; a belief or assessment based on grounds short of proof
Example
In my opinion, this is the best solution.
在我看来，这是最好的解决方案。
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。
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。
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。
A1 adverb /wʌns/

Once

一次; 过去的某个时候
Meaning
one time only; at some time in the past; formerly
Example
I have been to Paris once in my life.
我一生中只去过一次巴黎。
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。
C1 noun /ˈɒktəɡən/

octagon

八边形
Meaning
A polygon with eight sides and eight angles.
Example
The stop sign is shaped like an octagon.
停车标志呈八边形。
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。
C1 noun ˈoʊʃən əˌsɪdɪfɪˈkeɪʃən

ocean acidification

海洋酸化
Meaning
The ongoing decrease in the pH of the Earth's oceans, caused by the absorption of carbon dioxide from the atmosphere.
Example
Ocean acidification is caused by atmospheric CO2 absorption.
海洋酸化是由大气中CO2的吸收引起的。
C2 adjective /ɒmˈnɪp.ə.tənt/

omnipotent

全能
Meaning
Having unlimited power; able to do anything; all-powerful.
Example
In many religions, God is considered omnipotent.
在许多宗教中，上帝被认为是全能的。
B1 adverb /əˈrɪdʒɪnəli/

originally

最初
Meaning
in the beginning, at first
Example
Originally, she wanted to be a doctor.
最初，她想成为一名医生。
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。
B2 verb /ˌoʊvərˈloʊd/

overload

过载
Meaning
to load with too much weight or cargo; to give too much work or information
Example
Don't overload the washing machine or it might break down.
不要过载洗衣机，否则它可能会坏掉。
C2 noun /ˌɑːpərˈtuːnɪzəm/

opportunism

机会主义
Meaning
The practice of taking advantage of opportunities regardless of principles or ethics.
Example
His decision was driven by opportunism, not values.
他的决定是由机会主义驱动的，而不是由价值观驱动的。
C1 noun ˌoʊ.vɚˈɡreɪ.zɪŋ

overgrazing

过度放牧
Meaning
The practice of allowing livestock to graze to the point of damaging vegetation.
Example
Overgrazing leads to soil erosion and loss of biodiversity.
过度放牧导致土壤侵蚀和生物多样性的丧失。
C2 noun /əˈprəʊ.bri.əm/

opprobrium

耻辱, 侮辱
Meaning
Harsh criticism or public disgrace.
Example
The scandal brought opprobrium on the politician.
丑闻给政治家带来了耻辱。
C1 verb /aʊst/

oust

驱逐
Meaning
To remove someone from a position or place of power or authority.
Example
The rebels ousted the dictator from power.
叛乱者将独裁者赶下台。
B1 verb /ˈɒpəreɪtɪŋ/

operating

操作
Meaning
to control or manage the functioning of something
Example
The company has been operating in this market for five years.
公司已经在这个市场运营了五年。
A1 verb /ˈoʊpən/

open

打开
Meaning
to move something so as to allow access; to begin
Example
Please open the door for me.
请为我打开门。
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。
C1 noun /ˈɑːdəsi/

odyssey

漫长的旅行
Meaning
a long, adventurous journey; a series of experiences
Example
Her career has been an odyssey of challenges and achievements.
她的职业生涯是一场挑战和成就的漫长旅行。
C1 adjective ˈɒptɪmaɪzd

optimized

优化, 改善, 更有效
Meaning
Made as fully perfect, functional, or effective as possible; improved to achieve maximum efficiency.
Example
The system has been optimized for faster performance.
系统已经针对更快的性能进行了优化。
C1 adjective /ˈɑp.ər.ə.tɪv/

Operative

有效的; 运行中的; 工作中的; 操作性的;
Meaning
Functioning; in effect; working; active;
Example
The new safety protocols became operative immediately after the accident.
新的安全协议在事故发生后立即生效。
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 noun /oʊliˈændər/

Oleander

夹竹桃
Meaning
a poisonous evergreen shrub with clusters of white, pink, or red flowers
Example
The beautiful oleander flowers bloomed in the garden despite their toxic nature.
美丽的夹竹桃花在花园里盛开，尽管它们有毒。
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。
C2 verb /ˈoʊɡəl/

ogle

色迷迷地看
Meaning
To look at someone with obvious sexual interest.
Example
He kept ogling the models on the runway.
他一直盯着跑道上的模特看。
C1 noun /ˌɑːsɪˈleɪʃən/

oscillation

摆动
Meaning
The movement back and forth at a regular speed.
Example
The oscillation of the pendulum controls the clock.
摆锤的摆动控制着时钟。
B2 verb /əˈblaɪdʒ/

oblige

迫使
Meaning
to compel or require someone to do something; to help or do a favor
Example
I would be happy to oblige you with the information you need.
我很乐意为你提供所需的信息。
B2 verb /ˌoʊvərˈwɛlm/

overwhelm

Meaning
to overpower someone emotionally or physically; to be too much to handle
Example
She was overwhelmed with gratitude after receiving the help.
C2 adjective /ˌɒbsəˈlɛsnt/

obsolescent

过时的
Meaning
Becoming outdated or on the way to becoming obsolete.
Example
The obsolescent technology could not compete with modern devices.
过时的技术无法与现代设备竞争。
B1 noun ˈɒk.sɪ.dʒən

oxygen

氧气。无色、无味的气体，是生命必不可少的成分。
Meaning
A colorless, odorless reactive gas, the chemical element of atomic number 8 and the life-supporting component of the air.
Example
Oxygen is vital for life.
氧气对生命至关重要。
B1 adjective /ˌoʊvərˈweɪt/

overweight

超重
Meaning
heavier than is considered healthy or normal
Example
The doctor advised him to lose weight as he was overweight.
医生建议他减肥，因为他超重。
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。
B2 noun /ˈoʊ.dər/

Odour

气味
Meaning
a distinctive smell, especially an unpleasant one
Example
The odour of fresh bread filled the kitchen.
新鲜面包的气味充满了厨房。
B1 noun /ˌɑk.jəˈpeɪ.ʃən/

Occupation

职业; 工作; 占领
Meaning
a job or profession; the action of taking control of a place
Example
Teaching is her chosen occupation.
教学是她选择的职业。
C1 verb /əˈfɪʃieɪt/

officiate

主持
Meaning
To perform official duties, especially in a ceremony or as a referee.
Example
The priest will officiate the wedding ceremony.
牧师将主持婚礼仪式。
C1 adjective /əbˈtjuːs/

Obtuse

迟钝的; 愚笨的; 理解慢
Meaning
annoyingly insensitive or slow to understand; lacking in intelligence or perception
Example
He was being deliberately obtuse about the instructions.
他故意在指令上表现得迟钝。
A1 conjunction /ɔːr/

or

或
Meaning
used to link alternatives
Example
You can have tea or coffee.
你可以喝茶或咖啡。
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 adverb /ˈəʊvəli/

overly

过度
Meaning
to an excessive degree or extent
Example
She was overly concerned about the results.
她对结果过于担忧。
C1 noun /ˈoʊvərˌsiːər/

overseer

监督员
Meaning
a person who supervises work or workers; a manager
Example
The overseer made sure the workers followed safety rules.
监督员确保工人遵守安全规则。
C1 noun ɔːrˈdiːl

ordeal

艰难的考验
Meaning
A physical or mental painful experience that must be endured
Example
Surviving the wilderness was a tough ordeal for them.
在野外生存对他们来说是一场艰难的考验。
C1 adverb /ˈaʊtwədli/

Outwardly

表面上; 外观上;
Meaning
on the surface; externally; in appearance
Example
Outwardly, he seemed calm, but inside he was nervous.
表面上，他看起来很冷静，但内心却很紧张。
B2 noun /ˈaʊtˌbreɪk/

outbreak

爆发
Meaning
a sudden start or occurrence of something unpleasant, like disease or violence
Example
There was an outbreak of flu in the city.
城市中爆发了流感。
B2 adjective /ˈɔː.rəl/

Oral

口头的；与嘴巴相关的
Meaning
spoken rather than written; relating to the mouth
Example
The oral examination will test your speaking skills.
口头考试将测试你的口语技能。
B2 noun /ɔːrˈɡæn.ɪk ˈfɑːr.mɪŋ/

organic farming

有机农业
Meaning
Farming method that avoids synthetic chemicals and fertilizers, using natural methods instead.
Example
Organic farming improves soil health and reduces pollution.
有机农业改善了土壤健康并减少了污染。
A2 adverb; noun /ˌaʊtˈdɔːrz/

outdoors

在户外
Meaning
outside a building; the natural environment outside
Example
We spent the whole afternoon outdoors enjoying the fresh air.
我们整个下午都在户外享受新鲜空气。
C2 verb /əbˈvɜːrt/

obvert

反转
Meaning
To turn something so as to face in a different direction; in logic, to convert a proposition by negating both subject and predicate.
Example
The teacher asked the students to obvert the statement for practice.
老师要求学生练习将声明进行奥贝特。
B2 noun /ˈaʊtˌskɜːrt/

outskirt

城市郊区
Meaning
the outer edge or border of a town or city
Example
They built a new factory on the outskirts of the city.
他们在城市郊区建了一家新工厂。
B2 noun oʊˈbiː.sə.t̬i

obesity

肥胖症
Meaning
The condition of being grossly fat or overweight.
Example
Obesity increases the risk of diabetes and heart disease.
肥胖症增加糖尿病和心脏病的风险。
C2 adjective /ɑːlˈfæktəri/

olfactory

Meaning
Relating to the sense of smell.
Example
The perfume activated her olfactory nerves immediately.
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。
C2 noun /ɒkˈteɪvoʊ/

octavo

八开 (通过将纸张折叠成八个部分而产生的书籍大小)
Meaning
A size of book page resulting from folding a sheet of paper into eight leaves (sixteen pages).
Example
The old library contained rare octavo editions of Shakespeare.
这座古老的图书馆里有莎士比亚的稀有八开版书籍。
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 adjective /əˈbliːk/

Oblique

倾斜; 对角线; 间接或回避
Meaning
slanting; diagonal; indirect or evasive
Example
The artist drew an oblique line across the canvas.
艺术家在画布上画了一条倾斜的线。
B1 adjective, adverb /ˈoʊvərɔːl/

overall

总体上
Meaning
in general or as a whole
Example
Overall, the project has been successful.
总体上，项目已成功。
C1 adjective /ˈɒm.ɪ.nəs/

Ominous

不祥的; 威胁的
Meaning
giving the impression that something bad will happen; threatening; foreboding
Example
The dark clouds looked ominous before the storm.
暴风雨前，黑云看起来预示着灾难。
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。
C2 adjective /ˈəʊ.dər.əs/

Odorous

芬芳的; 香气的
Meaning
having a strong smell; fragrant; aromatic
Example
The garden was filled with odorous flowers.
花园里充满了芬芳的花朵。
A1 preposition /ʌv/

of

的
Meaning
expressing the relationship between a part and a whole
Example
The book is on the table, in front of the window.
书在桌子上，在窗户前。
B2 adjective, verb /əbˈskjʊr/

obscure

模糊
Meaning
Not clearly expressed or understood; to make something difficult to see or understand.
Example
The meaning of the poem was obscure to most readers.
诗的意义对大多数读者来说是模糊的。