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C2 noun /ˈʌŋkʃən/

unction

涂抹
Meaning
The act of anointing as part of a religious or ceremonial ritual; excessive or insincere flattery.
Example
The priest performed the holy unction with solemnity.
牧师庄重地进行了神圣的涂抹仪式。
C1 adjective /ʌnˈkæni/

uncanny

不可思议
Meaning
Strange or mysterious, especially in an unsettling way.
Example
She has an uncanny ability to predict the future.
她有一种不可思议的能力来预测未来。
B1 adjective /ʌnˈseɪf/

Unsafe

不安全; 危险的;
Meaning
involving or causing danger or risk; not protected from harm
Example
It is unsafe to walk alone in this neighborhood at night.
晚上在这个社区独自行走是不安全的。
B2 noun /ʌnəˈbɪləti/

unability

无能
Meaning
the state of being unable to do something; incapacity
Example
His unability to solve the problem caused delays in the project.
他解决问题的无能导致了项目的延误。
B1 adverb /ˌʌpsaɪd ˈdaʊn/

Upside-down

倒过来
Meaning
with the upper part at the bottom; in or into a reversed position
Example
The picture was hanging upside-down on the wall.
图片倒挂在墙上。
B2 adjective /ˈʌpˌraɪt/

Upright

诚实且道德正确；垂直或挺立的姿势
Meaning
honest and morally correct; vertical or erect in position
Example
She is known for being an upright and honest businesswoman.
她以诚实和正直的商业女性而闻名。
C2 adjective /ʌnˈflɛdʒd/

unfledged

未经训练的
Meaning
Inexperienced, immature, or not fully developed.
Example
The unfledged writer struggled to complete his first novel.
这个未经训练的作家难以完成他的第一本小说。
B2 adjective /ʌnˈkɒmən/

uncommon

不常见
Meaning
rare, unusual, or remarkable
Example
It is uncommon to see snow in this region.
在这个地区看到雪是不常见的。
C1 adjective /ˌʌnəˈfɛktɪd/

unaffected

不受影响的, 自然的
Meaning
Not influenced or touched by something; genuine and natural.
Example
He remained unaffected by the criticism and kept working hard.
他对批评毫不受影响，继续努力工作。
C2 verb /ˌʌn.dɪˈsiːv/

undeceive

解惑
Meaning
To free someone from a misconception or false belief.
Example
She tried to undeceive him about the false rumors.
她试图让他摆脱这些错误的谣言。
C2 verb /ʌpˈbreɪd/

upbraid

斥责
Meaning
To scold or criticize someone harshly.
Example
The teacher upbraided the student for being late again.
老师因为学生再次迟到而训斥了他。
A2 adjective /ʌnˈlʌki/

Unlucky

倒霉; 不幸运
Meaning
having bad luck; unfortunate
Example
He was unlucky to miss the winning shot.
他很倒霉错过了获胜的投篮。
B2 adjective /ʌnˈfeɪ.vər.ə.bəl/

Unfavourable

不利的; 逆境的
Meaning
not helpful or advantageous; adverse
Example
The weather conditions were unfavourable for our outdoor event.
恶劣的天气条件不利于我们的户外活动。
A1 verb /juːz/

use

使用
Meaning
to employ something for a purpose; to take advantage of
Example
I use my computer for work and entertainment.
我用我的计算机来工作和娱乐。
B2 adjective /ˌʌndɪˈnaɪəbl/

Undeniable

不容置疑
Meaning
impossible to deny or dispute; clearly true
Example
The evidence of his guilt was undeniable.
他的罪行证据是不容置疑的。
C2 adjective /juːˈbɪkwɪtəs/

ubiquitious

无处不在
Meaning
Present, appearing, or found everywhere.
Example
Smartphones have become ubiquitous in modern society.
智能手机已经在现代社会中无处不在。
B2 adjective /ʌnˌkənˈdɪʃ.ən.əl/

Unconditional

无条件的
Meaning
not subject to any conditions; complete and absolute
Example
She offered her unconditional support to her friend in need.
她在朋友需要时提供了无条件的支持。
A1 pronoun /ʌs/

us

我们
Meaning
used to refer to the speaker and one or more other people as the object of a verb or preposition
Example
She gave us a gift.
她给了我们一个礼物。
B2 adjective /ʌn.rɪˈleɪ.tɪd/

Unrelated

无关的; 不相关
Meaning
having no connection or relationship; not connected by family ties
Example
The two incidents were completely unrelated to each other.
这两个事件完全无关。
C1 noun /ˌʌl.tɪˈmeɪ.təm/

Ultimatum

最后通牒
Meaning
a final demand or statement of terms, the rejection of which will result in retaliation
Example
The boss gave him an ultimatum: improve or be fired.
老板给了他一个最后通牒：要么改进，要么被解雇。
C1 adjective /ʌnˈɒnəd/

unhonoured

未受尊敬的
Meaning
not respected or given the recognition that is deserved; treated without honor
Example
He felt unhonoured after his years of service were ignored.
他的多年服务被忽视后，他感到自己未受尊敬。
B2 adjective /ʌnprəˈfɛʃ.ən.əl/

Unprofessional

不专业
Meaning
not conforming to the standards expected in a particular profession
Example
His unprofessional behavior led to his dismissal from the company.
他的不专业行为导致他被公司解雇。
C2 noun /ˌjuːnɪˈtɛəriən/

unitarian

一神论者
Meaning
A person who believes that God exists as one entity rather than as a Trinity; a member of a religious denomination that emphasizes individual freedom of belief.
Example
The Unitarian church is known for its inclusive and open-minded approach.
一神论教会以其包容和开放的思想方式而闻名。
B2 adjective /ˈʌl.tɪ.mət/

Ultimate

最终的; 极致的; 终极的
Meaning
being the best or most extreme example of its kind; final; last
Example
This is the ultimate test of your skills.
这是你技能的终极考验。
B2 adjective /ˌʌnəˈweər/

Unaware

无意识的; 不知道的; 没有意识
Meaning
not knowing or realizing; having no knowledge of something
Example
She was completely unaware of the danger.
她完全没有意识到危险。
C1 adverb /ˌʌnkənˈvɛnʃənəli/

unconventionally

非传统地
Meaning
in a way that is not based on or conforming to accepted standards or norms
Example
She dresses unconventionally, mixing bold colors and patterns that surprise everyone.
她穿着非传统地，混搭大胆的颜色和图案，让每个人都感到惊讶。
B1 adjective /ˈjuːnɪfɔːrm/

Uniform

制服
Meaning
consistent; identical; standardized
Example
All students must wear a uniform to school.
所有学生必须穿制服上学。
C2 adjective /ˌʌn.təˈwɔːrd/

untoward

意外的
Meaning
Unexpected and inappropriate or inconvenient.
Example
The meeting ended without any untoward incidents.
会议在没有任何意外事件的情况下结束。
C2 noun /ˈʌndərlɪŋ/

underling

下属
Meaning
a person of low rank or importance; a subordinate
Example
The manager ordered his underlings to finish the task quickly.
经理命令他的下属快速完成任务。
B2 adjective /ˌʌnɪnˈtenʃənəl/

Unintentional

非故意的；意外的
Meaning
not done on purpose; accidental
Example
The damage to the car was unintentional.
车的损坏是非故意的。
B2 adjective /ˌʌnrɪˈzɒlvd/

unresolved

未解决的
Meaning
not solved or settled; remaining undecided or unclear
Example
The dispute remains unresolved despite several meetings.
尽管开了几次会议，这个争议仍未解决。
B1 adjective /ʌnˈfɔːr.tʃən.ət/

Unfortunate

不幸的；遗憾的
Meaning
having bad luck; regrettable or unlucky
Example
It was unfortunate that the meeting was cancelled at the last minute.
很不幸的是，会议在最后一刻被取消了。
B1 adjective /ʌnˈwel/

Unwell

不舒服; 生病
Meaning
not in good health; feeling sick or ill
Example
She has been feeling unwell since yesterday.
她从昨天开始感到不舒服。
B2 adjective /ʌnˈiːkwəl/

Unequal

不平等; 不公正;
Meaning
not the same in quantity, size, or value; not fair or just
Example
The distribution of wealth is unequal in many countries.
财富的分配在许多国家是不平等的。
C2 adjective /ʌnəˈpiːzd/

unappeased

不平息的
Meaning
Not satisfied or calmed; still feeling discontent or anger
Example
Despite the apology, she remained unappeased.
尽管道歉，她仍然不平息的。
C2 verb /ˈʌndərˌraɪt/

underwrite

Meaning
To guarantee financial support, especially by agreeing to cover losses or risks; in insurance, to assess and accept risks.
Example
The bank agreed to underwrite the company's new bond issue.
B1 adjective /ʌnˈkaʊntəbəl/

Uncountable

无法计数的; 无穷的
Meaning
too many to be counted; innumerable; infinite in quantity
Example
There are uncountable stars in the night sky.
夜空中有无数的星星。
A2 adjective /ʌnˈtaɪdi/

Untidy

凌乱的; 无序的;
Meaning
not neat or orderly; messy and disorganized
Example
Her untidy room was filled with clothes scattered everywhere.
她凌乱的房间充满了四处散落的衣服。
C1 adjective /ˌʌnbɪˈliːvɪŋ/

unbelieving

不相信的
Meaning
Not willing or able to believe; skeptical or doubtful
Example
She gave him an unbelieving look when he claimed to have met a celebrity.
当他声称见过一位名人时，她给了他一个不相信的眼神。
C2 verb /ʌnˈjoʊk/

unyoke

解开
Meaning
To release from a yoke or to free from restraint or obligation.
Example
The farmer unyoked the oxen after a long day of work.
农民在长时间工作后解开了牛的套索。
C2 adjective /ˌʌnrɪˈmɪtɪŋ/

unremitting

不断的
Meaning
Never relaxing or stopping; persistent.
Example
Her unremitting efforts finally paid off.
她不懈的努力终于得到了回报。
B2 adjective /ʌnˈsuːtəbl/

Unsuitable

不适合; 不合适
Meaning
not fitting or appropriate for a particular purpose or situation
Example
This formal dress is unsuitable for a casual beach party.
这件正式的衣服不适合参加随意的海滩派对。
C1 adjective /ˌʌn.əˈdʌl.tə.reɪ.tɪd/

Unadulterated

纯净的
Meaning
not mixed or diluted with any different or extra elements; pure
Example
She felt unadulterated joy when she heard the news.
当她听到这个消息时，她感到纯净的快乐。
C2 noun /juːˌtɪlɪˈtɛəriənɪzəm/

utilitarianism

功利主义
Meaning
The ethical theory that actions are right if they are useful or for the benefit of the majority.
Example
Utilitarianism suggests that we should act to maximize overall happiness.
功利主义认为我们应该采取行动，以最大化整体幸福。
C1 adjective /ʌnˈwɪtɪŋ/

unwitting

无意的
Meaning
Not aware of what is happening; done without realizing.
Example
She became an unwitting participant in the scam.
她成了这场骗局中的一个无意的参与者。
C1 adjective + noun ʌnˈpresɪdentɪd ˈnɒlɪdʒ

unprecedented knowledge

前所未有的知识
Meaning
Information or understanding that has never been obtained or achieved before.
Example
Artemis will provide unprecedented knowledge about the solar system.
阿尔忏将提供关于太阳系的前所未有的知识。
B2 adjective /ʌnˈwaɪz/

unwise

不明智
Meaning
Showing poor judgment; not sensible or prudent.
Example
It would be unwise to invest all your money in one company.
把所有的钱都投入一家公司的做法不明智。
C2 adjective /ʌnˈælɔɪd/

unalloyed

纯净
Meaning
Pure, complete, and not mixed with anything else.
Example
She felt unalloyed joy at the news of her success.
她听到成功的消息时感到纯粹的喜悦。
C1 noun /ˈʌndərˌteɪkər/

undertaker

殡葬员
Meaning
A person whose job is to prepare the dead for burial and arrange funerals.
Example
The undertaker prepared the body for the funeral service.
殡葬员为葬礼服务准备了尸体。
B2 adjective /ˈjuː.nɪ.faɪd/

unified

统一
Meaning
Made into a whole or joined together.
Example
A unified approach fosters better outcomes.
统一的方法促进了更好的结果。
C2 adjective /ʌnˈtɛmpərd/

untempered

失控的
Meaning
not moderated or softened; lacking proper balance or control
Example
The untempered anger of the crowd caused chaos.
人群的失控愤怒引发了混乱。
B2 adjective /ˌʌnkənˈvɪnsɪŋ/

Unconvincing

不可信
Meaning
failing to persuade or impress; not believable or credible
Example
His excuse for being late was completely unconvincing.
他因迟到而给出的借口完全不可信。
B2 noun ˌɜːbənaɪˈzeɪʃən

urbanization

城市化
Meaning
The process by which towns and cities are formed and become larger as more people begin living and working in central areas.
Example
Urbanization leads to more developed infrastructure.
城市化导致更先进的基础设施。
A2 preposition /əˈpɒn/

upon

之后
Meaning
on or immediately after
Example
Upon hearing the news, he rushed to the hospital.
听到消息后，他赶到医院。
B1 adjective /ʌnˈfeər/

Unfair

不公平; 不正当;
Meaning
not right or just; treating people in a way that favors some over others
Example
It's unfair to blame her for something she didn't do.
指责她做了她没有做的事是不公平的。
C2 adjective /ˈʌndjʊləs/

undulous

波浪形的
Meaning
Having a wavy surface or form.
Example
The artist painted the undulous sea at sunset.
艺术家在日落时画了波浪形的海洋。
B2 noun ˌjuːtɪlaɪˈzeɪʃən

utilization

利用
Meaning
The action of making practical and effective use of something.
Example
Increased plastic utilization calls for better waste management.
塑料的使用增加要求更好的废物管理。
B2 adverb /ʌnˈkɒnʃəsli/

unconsciously

无意识地
Meaning
without being aware of one's actions or surroundings
Example
She unconsciously tapped her foot to the rhythm of the music.
她无意识地跟着音乐的节奏轻轻跺脚。
C2 noun /ˈjuːʒəri/

usury

高利贷
Meaning
The practice of lending money at unreasonably high interest rates.
Example
The law strictly prohibits usury.
法律严格禁止高利贷。
C1 adjective /ˌʌndərˈsaɪzd/

undersized

尺寸过小
Meaning
Smaller than the usual or expected size.
Example
The undersized puppy struggled to keep up with its siblings.
这只尺寸过小的小狗很难跟上它的兄弟姐妹。
C1 adjective /ʌnˈsəʊʃəbl/

unsociable

不合群的
Meaning
not enjoying the company of others; avoiding social interaction
Example
He became unsociable after moving to a new city.
搬到新城市后，他变得不合群。
C1 verb /ˌʌndəˈreɪt/

underrate

低估
Meaning
to fail to recognize the full value or importance of something or someone
Example
Many people underrate the benefits of regular exercise.
许多人低估了规律锻炼的好处。
A1 noun /ˌjuːnɪˈvɜːrsɪti/

university

大学
Meaning
an institution of higher education and research, which grants academic degrees
Example
She is studying law at the university.
她在大学学习法律。
C2 verb /ʌnˈkaʊtʃ/

uncouch

从沙发上移开（罕见用法）
Meaning
to remove from a couch or to release from being laid down (rare/archaic usage)
Example
The surgeon attempted to uncouch the cataract.
外科医生试图去除白内障。
B1 adjective /ʌnɪmˈplɔɪd/

Unemployed

失业
Meaning
without a job; not having paid work
Example
He has been unemployed for six months now.
他已经失业六个月了。
A1 adjective /ˈjuːs.fəl/

Useful

有用的; 实用的
Meaning
having a beneficial purpose; practical
Example
This tool is very useful for fixing problems.
这个工具对解决问题非常有用。
C1 adjective /ˌjuːnɪˈsɛljʊlər/

unicellular

单细胞
Meaning
Consisting of a single cell.
Example
Amoebas are unicellular organisms.
变形虫是单细胞生物。
C2 adjective /ˌʌnsɛrəˈmoʊniəs/

unceremonious

不拘礼节/粗鲁
Meaning
Done without formality or courtesy; abrupt or rude.
Example
He made an unceremonious exit from the party.
他从派对上不拘礼节地离开。
C1 adjective /ʌnˈkʌltʃəd/

Uncultured

不文明的; 无文化的
Meaning
lacking good manners, refinement, or education; uncivilized
Example
His uncultured behavior embarrassed everyone at the dinner party.
他在晚宴上的不文明行为让所有人感到尴尬。
C2 adjective /ʌnˈʌtərəbl/

unutterable

难以言喻
Meaning
Too great, intense, or awful to be expressed or described in words.
Example
She was filled with unutterable joy at the news of her success.
她听到成功的消息时充满了难以形容的喜悦。
B2 noun /ʌnˈkaɪndnəs/

unkindness

不友善
Meaning
lack of kindness; cruel or inconsiderate behavior
Example
His unkindness hurt her feelings deeply.
他的不友善深深伤害了她的感情。
B2 adjective /ʌnˈfeɪθ.fəl/

Unfaithful

不忠诚
Meaning
not loyal or true to a spouse, partner, or commitment
Example
He was unfaithful to his wife for many years.
他对妻子不忠诚多年。
B1 verb /ʌnˈpæk/

unpack

拆开
Meaning
to remove items from a container; to explain or analyze something in detail
Example
After arriving home, she began to unpack her suitcase.
到家后，她开始拆开自己的行李箱。
C2 adjective /ʌnˈwəʊntɪd/

unwonted

不寻常
Meaning
Unusual, uncommon, or out of the ordinary.
Example
She spoke with an unwonted gentleness that surprised everyone.
她以一种不寻常的温柔说话，令所有人都感到惊讶。
C2 adjective /juːˈʒʊəriəs/

usurious

高利贷的
Meaning
Charging excessively high interest rates on loans.
Example
The bank was accused of offering loans at usurious rates.
该银行被指控以高利贷利率提供贷款。
B1 adverb /ʌnˈjuːʒuəli/

unusually

异常地
Meaning
in a way that is not typical or expected; to an uncommon degree
Example
It was unusually cold for this time of year.
对一年中的这个时候来说，天气异常寒冷。
B2 verb /ˌʌndərˈɛstɪmeɪt/

underestimate

低估
Meaning
To judge something as less important or smaller than it really is.
Example
Never underestimate the power of teamwork.
永远不要低估团队合作的力量。
C1 adjective /ˌʌnˈpɑr.də.nə.bəl/

Unpardonable

不可宽恕的
Meaning
too bad to be forgiven; inexcusable
Example
His betrayal of trust was an unpardonable offense.
他的背叛是不可原谅的罪行。
C2 adjective /ˈʌndjʊleɪtɪŋ/

undulating

波动的
Meaning
Having a smoothly rising and falling form or motion like waves.
Example
We drove through undulating hills.
我们驱车穿过起伏的山丘。
B1 adjective /ˌʌnbɪˈliːvəbəl/

Unbelievable

难以置信
Meaning
impossible to believe; extremely surprising or remarkable
Example
The magician's performance was absolutely unbelievable.
魔术师的表演简直令人难以置信。
C1 adjective /ˌʌnəˈteɪnəbl/

unattainable

无法实现的
Meaning
impossible to achieve, reach, or accomplish
Example
For many, becoming a professional athlete remains an unattainable dream.
对许多人来说，成为职业运动员仍然是一个无法实现的梦想。
B2 adverb /ʌnˈplɛzəntli/

unpleasantly

令人不快地
Meaning
in a way that causes discomfort, annoyance, or displeasure; in an unfriendly or disagreeable manner
Example
The room was unpleasantly hot during the afternoon.
下午房间里热得令人不快。
B2 adjective /ˌʌn.əkˈsep.tə.bəl/

Unacceptable

不可接受
Meaning
not satisfactory or allowable; not acceptable
Example
The quality of work was completely unacceptable.
工作质量完全不可接受。
A2 adjective /ʌnˈhæp.i/

Unhappy

不快乐; 难过
Meaning
not happy; feeling sad or displeased; unfortunate or undesirable
Example
He was unhappy with the results of his exam.
他对考试结果感到不满。
C1 adjective /ˌʌnəˈkaʊntəbl/

unaccountable

无法解释
Meaning
Not able to be explained or justified.
Example
She felt an unaccountable fear as she entered the dark room.
她进入黑暗的房间时感到无法解释的恐惧。
B2 adjective /ˌʌnəˈveɪləbəl/

unavailable

不可用
Meaning
Not able to be obtained, reached, or used; not present or accessible.
Example
The manager was unavailable to take calls during the meeting.
经理在会议期间不可用，无法接听电话。
C2 adjective /ʌpˈrɔːr.i.əs/

uproarious

极其滑稽
Meaning
Extremely funny or noisy; causing loud laughter or commotion.
Example
The comedian's jokes were absolutely uproarious.
喜剧演员的笑话绝对是极其滑稽的。
C2 noun juːˈbɪkwɪti

ubiquity

普遍性
Meaning
The fact of appearing everywhere or of being very common.
Example
The ubiquity of smartphones has transformed communication.
智能手机的普遍性改变了通信方式。
C1 adjective /ʌnˈsiːmli/

unseemly

不得体
Meaning
Not proper or appropriate in behavior or appearance; unbecoming.
Example
His unseemly remarks embarrassed everyone at the dinner table.
他不得体的言论让晚餐桌上的每个人都感到尴尬。
B1 verb /ˈʌpˌɡreɪd/

upgrade

升级
Meaning
to raise something to a higher standard, improve
Example
We decided to upgrade the software to the latest version.
我们决定将软件升级到最新版本。
C2 adverb /ʌnˈɜːrɪŋli/

unerringly

毫无错误
Meaning
Without making any mistakes; always accurate
Example
The archer aimed unerringly at the target.
弓箭手毫无错误地瞄准了目标。
B1 adjective /ˈɜːrdʒənt/

Urgent

紧急
Meaning
requiring immediate action or attention; pressing
Example
The patient needs urgent medical attention.
病人需要紧急医疗照顾。
B2 adjective /ʌnˈfɪt/

Unfit

不适合; 不适当;
Meaning
not in good physical condition; unsuitable or inappropriate
Example
He was declared unfit for military service due to his poor health.
由于健康状况差，他被宣判不适合军事服务。
C1 noun ˌʌndərˈprɪvəlɪdʒd ɡruːps

underprivileged groups

贫困群体
Meaning
Groups of people who lack basic necessities or advantages that are available to other members of society.
Example
Underprivileged groups benefit from social initiatives.
贫困群体从社会倡议中受益。
A2 adjective /ˈʌɡ.li/

Ugly

丑陋的; 可憎的; 可怕的
Meaning
unpleasant or repulsive in appearance; morally reprehensible
Example
The old building looked ugly after years of neglect.
这座老建筑在多年疏忽之后看起来很丑。
B2 verb /ʌnˈveɪl/

unveil

揭示
Meaning
to reveal or disclose something, especially in a formal manner
Example
The company will unveil a new product next week.
公司将在下周揭示一款新产品。
B2 adverb /ʌnˈnesəserəli/

Unnecessarily

不必要地
Meaning
to a greater extent than is needed; without necessity
Example
Don't worry unnecessarily about the exam.
不要为考试不必要地担心。
C1 adjective ʌnˈmætʃt

unmatched

无与伦比
Meaning
Not equaled or rivaled by any other; without equal.
Example
The freedom fighters showed unmatched bravery.
自由战士们展示了无与伦比的勇气。
C1 adjective ʌnɪnˈhæbɪtəbəl

uninhabitable

不可居住
Meaning
Not suitable or safe for people to live in.
Example
Rapid urbanization can make cities uninhabitable.
快速城市化可能使城市变得无法居住。
B1 noun /ʌnˈhæp.i.nəs/

unhappiness

不快乐
Meaning
the state of being unhappy; sadness or dissatisfaction
Example
Her constant unhappiness affected everyone around her.
她持续的不快乐影响了周围的每一个人。
B2 adjective /ʌnˈkwɒl.ɪ.faɪd/

Unqualified

不合格的; 无资格的;
Meaning
not having the necessary skills or qualifications; complete or absolute
Example
He was unqualified for the engineering position due to lack of experience.
他因缺乏经验而不适合这个工程职位。
B2 adverb /ˈʌt.ə.li/

Utterly

完全地; 绝对地; 完整地
Meaning
completely; absolutely; totally
Example
The movie was utterly boring and I fell asleep.
电影完全无聊，我睡着了。
B2 adjective /ˌʌnrɪˈlaɪəbl/

Unreliable

不可靠的; 不能被信任或依赖
Meaning
not dependable; not able to be trusted or relied upon
Example
The old car is unreliable and breaks down frequently.
这辆老车不可靠，常常坏掉。
B2 adjective /ˈʌt.moʊst/

Utmost

最极; 极限
Meaning
greatest; most extreme; maximum possible
Example
She showed utmost care while handling the fragile items.
她在处理脆弱物品时表现出最大的关心。
B2 adjective ʌnˈprɛsɪˌdɛntɪd

unprecedented

前所未有
Meaning
Never done or known before; without previous example.
Example
Unprecedented advancements in science changed human lives.
科学上的前所未有的进展改变了人类的生活。
B2 adjective /ˌʌnɪˈmædʒənəbəl/

Unimaginable

难以想象的
Meaning
impossible to conceive; beyond imagination
Example
The scale of destruction was unimaginable until we saw it firsthand.
毁灭的规模是难以想象的，直到我们亲眼看到。
B2 adjective /ʌnˈtʃeɪndʒɪŋ/

unchanging

不变的
Meaning
remaining the same over time; not changing
Example
Her love for her family was unchanging throughout the years.
她对家人的爱多年来始终不变。
C2 adjective /juːˈnɪsənənt/

unisonant

和谐的
Meaning
Sounding together or in harmony.
Example
The unisonant voices created a powerful effect.
和谐的声音创造了强大的效果。
C2 noun /ˈʌn.dɚˌstɔː.ri/

understory

下层植被
Meaning
The layer of vegetation beneath the main canopy of a forest.
Example
The understory of a rainforest is home to small mammals and insects.
雨林的下层植被是小型哺乳动物和昆虫的家园。
A2 noun /ˈʌndərwɛr/

Under wear

内衣
Meaning
clothing worn under other clothes, next to the skin
Example
She bought new underwear from the department store.
她在百货商店买了新的内衣。
C2 adjective /ʌnˈɡeɪnli/

ungainly

笨拙
Meaning
Awkward, clumsy, or lacking grace in movement or appearance.
Example
The tall boy moved in an ungainly manner.
那个高个男孩以笨拙的方式走动。
B2 adjective /ˈʌpˌhɪl/

Uphill

困难的; 需要巨大努力的; 向上的倾斜
Meaning
difficult; requiring great effort; sloping upward
Example
Learning a new language can be an uphill battle.
学习一门新语言可能是一个艰难的战斗。
A1 adjective /juːzd/

used

二手
Meaning
having already been used
Example
This is a used car.
这是一辆二手车。
C1 adjective /ʌnˈruːli/

Unruly

不守规矩的; 乱七八糟的;
Meaning
difficult to control or manage; disorderly and disruptive
Example
The unruly crowd refused to follow the safety instructions.
那群无法控制的人群拒绝遵循安全指令。
B1 adjective /ʌnˈeɪ.bəl/

Unable

无法
Meaning
lacking the power, skill, or means to do something
Example
He was unable to attend the meeting.
他无法参加会议。
C1 adjective /ˌjuːtɪlɪˈtɛəriən/

utilitarian

Meaning
Designed to be useful or practical rather than attractive; relating to the doctrine that actions are right if they are useful or for the benefit of a majority.
Example
The building had a simple utilitarian design.
B2 adjective /ʌnˈraɪp/

Unripe

未成熟的
Meaning
not fully developed or matured; not ready to be eaten
Example
The unripe bananas will turn yellow in a few days.
未成熟的香蕉几天后会变黄。
C1 verb /ʌnˈnɜːrv/

unnerve

失去信心
Meaning
to make someone lose confidence, courage, or composure
Example
The hostile questions began to unnerve the witness.
敌对问题开始让证人感到不安。
B2 adjective /ʌnˈtʃeɪndʒəbəl/

Unchangeable

不可改变的; 固定的;
Meaning
not able to be changed or altered; fixed and permanent
Example
The laws of physics are unchangeable principles that govern the universe.
物理法则是不变的原则，支配着宇宙。
C1 adjective /juːˈbɪkwɪtəs/

ubiquitous

无处不在
Meaning
Existing or being everywhere at the same time.
Example
Social media has become ubiquitous among young people.
社交媒体在年轻人中变得无处不在。
B1 adjective /ʌnˈʃʊr/

unsure

不确定的
Meaning
not certain or confident; feeling doubt
Example
She felt unsure about the decision.
她对这个决定感到不确定。