ordnance
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C2 noun /ˈɔːrdnəns/

ordnance

军火
Meaning
Military supplies including weapons, ammunition, and combat equipment.
Example
The army stored ordnance in a secure facility outside the city.
军队在城市外的一个安全设施中存储军火。
C1 verb /uːz/

ooze

渗透
Meaning
to slowly flow or leak out through small openings or pores
Example
Blood began to ooze from the small cut.
血液开始从小伤口渗透出来。
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 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。
A1 noun/adjective/adverb /ˌaʊtˈsaɪd/

outside

外面
Meaning
the external part or surface of something; beyond the boundary
Example
Children were playing outside in the yard.
孩子们在院子外面玩。
C2 noun /əbˈsɪdiən/

obsidian

黑曜石 (黑色的玻璃状火山岩)
Meaning
A hard, dark, glasslike volcanic rock formed by rapid solidification of lava.
Example
The knife was made from sharp obsidian.
刀是由锋利的黑曜石制成的。
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。
C2 noun /ˈaʊtˌrɪɡər/

outrigger

稳定结构
Meaning
a projecting structure on a boat, used for stability, or a boat fitted with such support
Example
The fisherman paddled his outrigger canoe across the lagoon.
渔民划着带有支撑的独木舟穿过泻湖。
A1 adjective /ˈʌðər/

other

其他
Meaning
used to refer to something different from the one already mentioned or known
Example
I don't want this one, I will take the other one.
我不想要这个，我会拿另一个。
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 /ˈɒrɪz(ə)n/

orison

祷告
Meaning
a prayer, especially a devout or formal one
Example
He whispered a quiet orison before going to sleep.
他在睡觉前低声祈祷。
C2 adjective /əbˈsiːkwɪəs/

obsequious

奉承
Meaning
Excessively obedient or attentive in a servile way.
Example
The waiter gave an obsequious bow to every customer.
服务员对每个顾客鞠了一躬。
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。
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。
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。
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。
B1 verb /oʊ/

owe

欠债
Meaning
to be under obligation to pay or repay; to be indebted
Example
I owe my success to my parents' support.
我将我的成功归功于父母的支持。
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。
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 /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。
A2 adjective /ˈɑp.ə.zɪt/

Opposite

相反的; 完全不同的; 面对面; 反向的;
Meaning
Contrary; completely different; facing each other; reverse;
Example
They have opposite views on politics but remain good friends.
他们在政治上的观点相反，但仍然是好朋友。
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。
C2 noun /ˈɔːrdʒi/

orgy

荒淫派对
Meaning
A wild party involving excessive indulgence, especially of a sexual nature.
Example
The novel described a scandalous orgy in a wealthy mansion.
小说描述了在一座富裕的豪宅里举行的丑闻般的荒淫派对。
B1 verb অকার্স

occurs

发生
Meaning
Happens or takes place, especially as a result of something.
Example
Snowfall occurs in regions with freezing temperatures.
在气温低于零度的地区会发生降雪。
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。
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 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。
B2 noun /ɒpˈtɪʃən/

optician

眼镜师
Meaning
A person who makes or sells glasses and contact lenses.
Example
The optician adjusted my new glasses to fit better.
眼镜师调整了我的新眼镜，以便更好地适应。
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。
C2 noun /ˈɒkjʊlɪst/

oculist

眼科医生
Meaning
An old-fashioned term for an eye doctor or ophthalmologist.
Example
The village oculist was known for treating various eye diseases.
村里的眼科医生以治疗各种眼病而闻名。
C1 adjective /ˌɒstɛnˈteɪʃəs/

ostentatious

炫耀的
Meaning
Characterized by a showy or pretentious display intended to impress others.
Example
He wore an ostentatious gold chain to the party.
他在派对上戴着一条炫耀的金链子。
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。
C1 verb /ˈɒs.ɪ.leɪt/

oscillate

在两个点或状态之间来回摆动或移动
Meaning
To swing or move back and forth between two points or states
Example
The stock market tends to oscillate during uncertain times.
股市在不确定的时期往往会波动。
A1 adjective /oʊld/

old

旧的
Meaning
having lived for a long time; not new or young
Example
He still drives his old car.
他仍然开着他的旧车。
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 noun /ˈɑn.set/

Onset

开始; 起始
Meaning
the beginning or early stages of something; the start of a medical condition
Example
The onset of winter brought heavy snowfall.
冬天的开始带来了大雪。
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。
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。
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。
C1 verb /ˌoʊvərˈriːtʃ/

overreach

过度伸展
Meaning
to go beyond what is proper, acceptable, or achievable; to overextend
Example
The politician overreached by making promises he couldn't keep.
那位政治家在做出无法兑现的承诺时，过度伸展了自己。
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.
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。
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。
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。
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。
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。
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。
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。
C1 adjective /ˌɔːrθəˈpiːdɪk/

orthopedic

与骨骼或肌肉畸形的矫正有关
Meaning
Relating to the correction of deformities of bones or muscles.
Example
She visited an orthopedic surgeon for her back pain.
她因为背痛去看了骨科医生。
C1 noun /ˈɔːr.ə.tɔːr.i/

oratory

演讲艺术
Meaning
The art of public speaking; skilled and confident delivery of speeches to an audience.
Example
His exceptional oratory skills won him the debate competition.
他出色的演讲技巧使他赢得了辩论比赛。
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 noun /əˈpoʊ.nənt/

Opponent

对手; 竞争者
Meaning
a person who disagrees with or resists a proposal or practice; someone who competes against another
Example
The chess player defeated his strongest opponent.
象棋选手击败了他最强的对手。
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。
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。
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 /əˌrɪʒ.əˈnæl.ə.ti/

Originality

原创性
Meaning
the quality of being novel or unusual; the ability to think independently and creatively
Example
The artist's work showed great originality and creativity.
艺术家的作品展示了极大的原创性和创造力。
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。
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。
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 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。
C1 adjective /ˈɔːrdɪnəl/

ordinal

序数
Meaning
Relating to the order or position of something in a sequence (first, second, third, etc.).
Example
The ordinal number 'third' indicates position in a sequence.
序数词'第三'表示在顺序中的位置。
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。
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。
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。
C1 noun /oʊˈbɪt.ʃu.er.i/

Obituary

讣告
Meaning
a notice of someone's death published in a newspaper; biographical account of deceased person
Example
The newspaper published his obituary yesterday.
报纸昨天发布了他的讣告。
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。
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。
B2 verb /ˌoʊvərˈduː/

overdo

做得过火
Meaning
to do something too much; to exaggerate or carry to excess
Example
Don't overdo the exercise on your first day at the gym.
第一天去健身房时不要运动过度。
B2 adjective /ˈɔɪl.i/

Oily

油腻的; 油覆盖的; 油滑的
Meaning
covered with oil; containing oil; greasy
Example
Her oily skin needs special care.
她的油腻皮肤需要特别护理。
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。
A1 adverb /ˈɔːfən/

often

经常
Meaning
frequently, many times
Example
I often visit my grandparents on weekends.
我经常在周末拜访我的祖父母。
A1 pronoun /ˈʌðərz/

others

其他
Meaning
people or things distinct from the ones already mentioned or known
Example
I like to spend time with others.
我喜欢和其他人一起度过时间。
B2 noun /ɒdz/

odds

可能性
Meaning
the likelihood or probability of something happening; chances for or against something
Example
The odds of winning the lottery are very low.
中彩票的机会非常小。
B1 noun /ˈɑp.ʃən/

Option

选项
Meaning
a thing that is or may be chosen; an alternative course of action
Example
You have the option to work from home or office.
你可以选择在家工作或在办公室工作。
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 /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。
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。
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.
C1 verb /ˌoʊvərˈrʌn/

overrun

侵占
Meaning
to spread over or occupy completely; to exceed a limit or time
Example
The garden was overrun with weeds.
花园被杂草淹没。
C2 verb /ˌoʊvərˈstraɪd/

overstride

跨越大步走
Meaning
To stride over something; to step across with long steps.
Example
He managed to overstride the narrow stream with ease.
他轻松地跨越了狭窄的溪流。
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 adjective /ˌaʊtˈlændɪʃ/

outlandish

奇异
Meaning
Looking or sounding bizarre or unfamiliar; strange.
Example
He wore an outlandish costume to the festival.
他穿着一件奇异的服装参加了节日。
C1 noun /əbˈzɜːvəns/

observance

遵守
Meaning
The practice of following a custom, rule, or religious law.
Example
The festival is held in observance of a centuries-old tradition.
该节庆是为了遵守一项百年传统而举行的。
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。
C1 adjective /ˌaʊt ən ˈaʊt/

out-and-out

完全
Meaning
complete; absolute; used to emphasize something extreme
Example
The speech was an out-and-out lie.
这个演讲是一个完全的谎言。
C1 noun /ɒpˈtɒmətri/

optometry

验光学
Meaning
The practice or profession of examining the eyes and prescribing corrective lenses.
Example
She studied optometry at the university to become an eye specialist.
她在大学学习验光学，成为一名眼科专家。
C1 noun /ˈaʊtriːtʃ/

outreach

援助扩展
Meaning
The act of providing services or support to people who might not otherwise have access to them.
Example
The charity launched a new outreach program for the homeless.
慈善机构为无家可归的人推出了一个新的援助扩展计划。
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 /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。
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。
A1 adjective /oʊˈkeɪ/

ok

好的
Meaning
used to indicate agreement, approval, or understanding
Example
Okay, let's go to the park.
好的，我们去公园。
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 ˈɑːb.fə.skeɪt

obfuscate

使模糊，掩盖，混淆
Meaning
Render obscure, unclear, or unintelligible.
Example
Politicians often obfuscate facts to mislead people.
政客们经常使事实变得模糊，以误导人民。
C1 noun /ˈɔr.i.ənt/

Orient

东方，尤其是东亚国家
Meaning
the East, especially countries of eastern Asia; to determine one's position or direction
Example
Many spices come from the Orient.
许多香料来自东方。
C1 adjective /əˈkʌlt/

occult

奥秘的
Meaning
Relating to mysterious, supernatural, or magical powers and practices.
Example
She had always been fascinated by the occult and its hidden knowledge.
她一直对奥科尔特及其隐藏的知识感到着迷。
C1 adjective /ˈɒptɪkəl/

optical

光学的
Meaning
related to or used in seeing or sight
Example
The optical illusion fooled everyone at the exhibition.
光学幻觉在展览会上迷惑了所有人。
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。
A1 preposition, adverb /ˈoʊvər/

over

在…上面
Meaning
across, on top of, or beyond
Example
The book is lying over the table.
书在桌子上面。
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 verb /ˈɑːbdʒərˌɡeɪt/

objurgate

严厉批评
Meaning
to scold or rebuke severely
Example
The teacher objurgated the student for being dishonest.
老师因为学生不诚实而严厉批评了他。
C1 adjective/adverb /ˌɒfˈhænd/

offhand

草率
Meaning
Without previous thought or preparation; casual and sometimes dismissive.
Example
She gave an offhand reply to his serious question.
她对他严肃的问题做出了一个草率的回答。
B1 noun /ˈɑb.stə.kəl/

Obstacle

障碍
Meaning
something that blocks or makes progress difficult; a barrier
Example
Bad weather was the main obstacle to our journey.
坏天气是我们旅行的主要障碍。
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。
B1 adjective /əˈbiː.di.ənt/

Obedient

顺从的
Meaning
willing to comply with orders or instructions; submissive
Example
The obedient student always follows the teacher's instructions.
听话的学生总是遵循老师的指示。
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。
B2 adjective /ˈɒp.tɪ.məl/

optimal

最优，最适合的
Meaning
Best or most favorable; the most effective under particular conditions.
Example
The optimal temperature for plant growth is around 25°C.
植物生长的最优温度大约是25°C。
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 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。
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。
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。
B2 verb /əˈrɪdʒɪneɪt/

originate

起源
Meaning
to come into existence; to begin; to create or produce
Example
The tradition originated in ancient times.
这个传统起源于古代。
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。
C2 noun /ˌɒktədʒəˈnɛəriən/

octogenarian

八十岁老人
Meaning
A person who is between 80 and 89 years old.
Example
The octogenarian still jogs every morning to stay healthy.
这位八十岁老人仍然每天早上跑步以保持健康。
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。
B2 adjective; verb (past participle) /ˈɒkjʊpaɪd/

occupied

被占用的；被占领的
Meaning
being in use or taken; filled or lived in; controlled or held by force
Example
The room is occupied, so please wait outside.
房间被占用，请在外面等候。
B2 noun/verb /ˈaʊtreɪdʒ/

outrage

愤怒
Meaning
A strong feeling of anger and shock; to arouse anger or shock.
Example
The unfair decision caused public outrage.
不公正的决定引起了公众的愤怒。
B2 adjective /ˌɑːp.təˈmɪs.tɪk/

optimistic

乐观的
Meaning
hopeful and confident about the future
Example
She is optimistic about the success of her new project.
她对新项目的成功持乐观态度。
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。
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。
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 /ˈɒptɪməm/

optimum

最优
Meaning
Most conducive to a favorable outcome; best.
Example
To achieve optimum results, we need to improve efficiency.
为了获得最佳结果，我们需要提高效率。