Unchangeable
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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 /ʌnˈkleɪmd/

Unclaimed

未认领的; 未要求的; 被遗弃或无主的
Meaning
not claimed by anyone; not demanded or requested; abandoned or ownerless
Example
The unclaimed luggage was stored in the airport's lost property department.
未认领的行李被存放在机场的失物招领处。
B2 adjective /ʌnˈberəbəl/

Unbearable

无法忍受
Meaning
too painful, annoying, or unpleasant to tolerate; impossible to endure
Example
The heat in the desert was unbearable.
沙漠中的热度是无法忍受的。
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。
C1 adjective /ˌʌnəbˈtruːsɪv/

unobtrusive

不引人注目
Meaning
not attracting attention; blending in without causing notice
Example
The security cameras are designed to be unobtrusive.
安全摄像头被设计成不引人注目。
C2 verb /ˈʌndjʊleɪt/

undulate

波动
Meaning
To move with a smooth, wave-like motion.
Example
The snake undulated across the sand.
蛇在沙滩上蜿蜒前行。
B2 adjective /ʌnˈlɪmɪtɪd/

unlimited

无限
Meaning
without any limits or restrictions
Example
The internet plan offers unlimited data for the whole month.
该互联网计划提供整个一个月的无限数据。
B2 adjective /ʌnˈfeɪv(ə)rəbəl/

unfavorable

不利
Meaning
not beneficial or advantageous; showing disapproval or opposition
Example
The proposal received an unfavorable response from the committee.
提案收到了委员会的负面回应。
A2 conjunction /ʌnˈlɛs/

unless

除非
Meaning
except if
Example
We won't go unless it stops raining.
除非雨停了，否则我们不去。
B2 adjective /ʌnˈbaɪəst/

unbiased

公正
Meaning
Not showing prejudice; impartial and fair.
Example
The report gave an unbiased view of the situation.
报告提供了该情况的公正观点。
B2 adjective /ʌnˌkənˈfɜːmd/

Unconfirmed

未确认; 未验证;
Meaning
not confirmed as true or definite; not verified or substantiated
Example
The report remains unconfirmed until we receive official verification.
报告在我们收到官方验证之前保持未确认状态。
C2 adjective /ˌʌltrəˈmʌndeɪn/

ultramundane

超凡
Meaning
Relating to things beyond the physical world; supernatural or transcendental.
Example
Philosophers often discuss ultramundane realities beyond human perception.
哲学家们常常讨论超越人类感知的超凡现实。
B2 adjective /ˌʌndɪˈsaɪdɪd/

Undecided

未决定的; 不确定的
Meaning
not having made a decision; uncertain
Example
She was undecided about which college to attend.
她对于选择哪个大学感到未决定。
B1 adjective /ʌnˈsɜːrtən/

Uncertain

不确定
Meaning
not able to be relied on; not known or definite; not having reliable knowledge
Example
I am uncertain about my future career plans.
我对未来的职业规划感到不确定。
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。
B2 adjective /ʌnˈiːzi/

Uneasy

不安的; 焦虑的; 不舒服的
Meaning
worried; anxious; uncomfortable; restless
Example
She felt uneasy about walking alone at night.
她在夜晚独自行走时感到不安。
C1 adjective /ʌnˈkuːθ/

uncouth

粗鲁
Meaning
Lacking good manners, refinement, or grace; awkward or rough.
Example
His uncouth behavior shocked the guests at the party.
他粗鲁的行为让聚会上的客人感到震惊。
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 verb /ˌʌndərˈɡoʊ/

undergo

经历
Meaning
to go through something, especially something unpleasant or difficult
Example
She had to undergo surgery to recover.
她不得不接受手术以恢复。
A2 noun /ˌʌndərˈstændɪŋ/

understanding

理解
Meaning
the ability to grasp the meaning, significance, or nature of something
Example
Her understanding of the issue was impressive.
她对这个问题的理解令人印象深刻。
B2 adjective /ʌnˈhɜːrt/

unhurt

毫发无损
Meaning
Not injured or harmed.
Example
She walked away from the accident unhurt.
她在事故中毫发无损。
B1 adjective /ʌnˈplɛz.ənt/

Unpleasant

令人不悦的
Meaning
not giving or causing pleasure; disagreeable
Example
The medicine had an unpleasant taste.
药物有一种令人不悦的味道。
A1 interjection /ʌ/

uh

呃
Meaning
a sound people make when they hesitate or are unsure what to say next.
Example
Uh, I’m not sure if that’s the right answer.
呃，我不确定这是不是正确的答案。
C1 adjective /ʌnˈbraɪdld/

unbridled

无法控制的
Meaning
Uncontrolled and unrestrained.
Example
The protesters showed unbridled enthusiasm for change.
抗议者展示了对改变的无法抑制的热情。
C1 adjective /ˌʌnfɔːrθˈkʌmɪŋ/

unforthcoming

不合作的
Meaning
Not willing to talk or provide information; uncooperative.
Example
The witness was unforthcoming about what he had seen.
证人对于他所见的情况不合作。
C1 adjective /ʌnˈdɔːntɪd/

Undaunted

无畏的; 勇敢的; 不屈的;
Meaning
not intimidated or discouraged by difficulty, danger, or disappointment
Example
Despite the setbacks, she remained undaunted in pursuing her goals.
尽管遇到挫折，她在追求目标时依然无畏。
C1 adjective ˌʌn.pəˈtɜːbd

unperturbed

不为某事烦恼或困扰；冷静且镇定
Meaning
Not worried or disturbed by something; calm and composed.
Example
She remained unperturbed despite the challenges.
尽管有挑战，她依然保持冷静。
B1 adjective /ˌʌnˈɪntrəstɪŋ/

uninteresting

无趣的
Meaning
not holding attention or curiosity; boring
Example
The lecture was uninteresting and difficult to stay focused on.
这次讲座很无趣，很难集中注意力。
C1 adjective /ʌnˈspiːkəbl/

unspeakable

难以形容
Meaning
too bad or shocking to be expressed in words
Example
The survivors endured unspeakable horrors during the war.
幸存者在战争中忍受了难以形容的恐怖。
B2 adjective /ʌnˈiːvən/

Uneven

不平; 粗糙
Meaning
not level or smooth; not regular or consistent
Example
The road was uneven and full of potholes.
那条路不平，充满了坑洞。
B2 adjective /ʌnˈsteɪbəl/

Unstable

不稳定
Meaning
likely to change; not steady or secure; unsteady
Example
The unstable economy made people worried about their jobs.
不稳定的经济让人们担心他们的工作。
C1 adjective /ˌʌnəˈsjuːmɪŋ/

unassuming

谦虚
Meaning
Not pretentious or arrogant; modest.
Example
Despite his success, he remained unassuming and humble.
尽管他取得了成功，他仍然谦虚和谦逊。
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。
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。
B2 noun /ˈʌndərˌteɪkɪŋ/

undertaking

事业
Meaning
A task, project, or responsibility that someone agrees to do.
Example
Starting a new company is a difficult undertaking.
创办新公司是一项艰巨的事业。
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。
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。
C1 adjective /ˌʌnəˈdɔːrnd/

unadorned

简单的，未装饰的
Meaning
Plain and simple; not decorated.
Example
The room was unadorned, with only a table and a chair.
房间简单，只有一张桌子和一把椅子。
B1 noun /ˈjuːnjən/

Union

联合
Meaning
the action of joining or combining; a political unit formed from separate states
Example
The union of the two companies created a powerful corporation.
两家公司的联合创造了一个强大的公司。
B1 adjective /ʌnˈklɪər/

unclear

不清楚
Meaning
not easy to understand; vague or ambiguous
Example
The instructions were unclear, so I asked for clarification.
说明不清楚，所以我要求澄清。
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 /ʌnˈspɛərɪŋ/

unsparing

无情的
Meaning
Showing no mercy or generosity; harsh or severe.
Example
The critic was unsparing in his review of the play.
评论家在他的剧评中毫不留情。
B2 adjective /ˌʌndɪˈstɜːrbd/

Undisturbed

未打扰
Meaning
not interrupted or interfered with; calm and peaceful
Example
She slept undisturbed for eight hours.
她睡了八个小时没有打扰。
B1 noun /juːˈten.səlz/

Utensils

餐具
Meaning
tools or implements used for cooking, eating, or serving food
Example
Please wash all the cooking utensils after preparing dinner.
请在准备晚餐后清洗所有的厨房用具。
B1 adjective /juːˈniːk/

Unique

独特的; 唯一的; 稀有的
Meaning
being the only one of its kind; unlike anything else
Example
Every snowflake is unique in its pattern.
每一片雪花在它的图案中都是独一无二的。
C1 adverb /ʌnˈnætʃrəli/

unnaturally

不自然地
Meaning
in a way that is not natural or normal; excessively or strangely
Example
He smiled unnaturally, making everyone feel uncomfortable.
他不自然地笑了，让每个人都感到不舒服。
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 /ˌʌnəkˈnɒlɪdʒd/

unacknowledged

未承认的
Meaning
Not recognized, admitted, or accepted; ignored or unnoticed
Example
Her contributions to the project went unacknowledged.
她对项目的贡献未被承认。
B2 adjective /ʌnˈlɔːfl/

Unlawful

非法; 不合法
Meaning
not authorized by law; illegal
Example
The court declared the search unlawful.
法院宣布搜索是非法的。
C1 adjective /ˌʌnbɪˈkʌmɪŋ/

unbecoming

不合适的
Meaning
Not proper or appropriate for a person; unsuitable.
Example
His rude behavior was unbecoming of a leader.
他的粗鲁行为对于一个领导者来说是不合适的。
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。
B2 verb /ˌʌndərˈteɪk/

undertake

承担
Meaning
to commit to and begin a task or project; to take on responsibility
Example
She decided to undertake a challenging project.
她决定承担一个具有挑战性的项目。
C1 noun /ˌʌnprɪˈdɪktəˌbɪləti/

unpredictability

不可预测性
Meaning
The quality of being impossible to predict or anticipate.
Example
The unpredictability of the weather made the trip uncertain.
天气的不可预测性使得旅行充满不确定性。
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.
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。
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。
C1 adjective /ʌnˈsɜːrvɪsəbəl/

Unserviceable

无法使用的; 有缺陷的
Meaning
not in working order; unable to be used; defective
Example
The old computer became unserviceable after the system crash.
那台旧电脑在系统崩溃后变得无法使用。
C1 adjective /ʌnˈkwes.tʃən.ə.bl̩/

Unquestionable

无可争议的; 确定的
Meaning
not able to be disputed or doubted; certain and beyond doubt
Example
Her honesty and integrity are unquestionable qualities.
她的诚实和正直是无可争议的品质。
C1 adjective ʌnˈtʃɑːtɪd

uncharted

未标记
Meaning
Not mapped or surveyed; unknown or unexplored.
Example
The mission aimed to explore uncharted areas of the planet.
该任务旨在探索星球上未标记的区域。
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。
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。
B2 adjective /ʌnˈɡreɪt.fəl/

Ungrateful

忘恩负义
Meaning
not feeling or showing thanks for something done or given; not appreciating kindness
Example
She felt he was ungrateful for all the help she had given him.
她觉得他对她给予的所有帮助都忘恩负义。
C2 adjective /ʌnˈtʃeɪst/

Unchaste

不道德的; 不纯洁的;
Meaning
not celibate; having engaged in sexual relations; lacking moral purity
Example
The conservative society considered her behavior unchaste and improper.
保守的社会认为她的行为不道德和不合适。
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 /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。
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。
C1 adjective /ˌʌnrɪˈfaɪnd/

unrefined

未精炼的
Meaning
not processed or purified; lacking polish or sophistication
Example
The unrefined oil must be processed before it can be used as fuel.
未精炼的石油在用作燃料之前必须进行加工。
C1 adjective /ʌnˈseɪvəri/

unsavory

令人不快
Meaning
Disagreeable, unpleasant, or morally offensive.
Example
The politician was linked to an unsavory scandal.
那位政治家与一宗令人不快的丑闻有关。
C1 verb /ˌʌndərˈsteɪt/

understate

低估
Meaning
To describe something as being less important or serious than it really is.
Example
He tends to understate his achievements.
他倾向于低估自己的成就。
A1 preposition/conjunction /ʌnˈtɪl/

until

直到
Meaning
up to the time of
Example
I will wait until you come back.
我会等到你回来。
B2 adjective /ʌnˈdʒʌst/

Unjust

不公正的; 错误的
Meaning
not fair or right; morally wrong
Example
The punishment was unjust for such a minor offense.
这个惩罚对于如此轻微的罪行来说是不公正的。
C1 adjective /ˌʌnsəˈfɪstɪˌkeɪtɪd/

unsophisticated

不复杂
Meaning
Lacking worldly experience, refinement, or complexity.
Example
The villagers led an unsophisticated but happy life.
村民过着简单而幸福的生活。
C1 adjective /ʌnˈfɛtərd/

unfettered

不受限制的
Meaning
not restricted or confined; free
Example
The artist enjoyed unfettered freedom of expression.
艺术家享受了无限制的表达自由。
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。
C2 noun /ˈʌm.brə/

Umbra

完全的阴影，太阳黑子的黑暗中心
Meaning
the fully shaded inner region of a shadow cast by an opaque object; the dark center of a sunspot
Example
During the eclipse, we stood in the moon's umbra.
在日食期间，我们站在月亮的本影中。
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。
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。
C2 noun /ʌnˈkloʊðɪŋ/

unclothing

脱衣
Meaning
the act or process of removing clothing
Example
The child quickly ran inside for unclothing after playing in the mud.
孩子在泥地玩耍后迅速跑进去脱衣。
B2 noun /ʌnˈrest/

Unrest

不安；动荡；社会或政治动乱
Meaning
a state of dissatisfaction and disturbance; social or political disorder
Example
The economic crisis led to widespread social unrest.
经济危机导致了广泛的社会不安。
C2 adjective /ʌkˈsɔːriəs/

uxorious

过度宠爱妻子
Meaning
excessively fond of or submissive to one's wife
Example
He was so uxorious that he agreed with everything his wife said.
他是如此的宠爱妻子，以至于同意了妻子说的每一件事。
B1 noun /ˌʌnɪmˈplɔɪmənt/

Unemployment

失业
Meaning
the state of being unemployed; lack of paid work
Example
The unemployment rate has increased significantly this year.
今年失业率显著上升。
C1 adjective /ʌnˈsteɪtɪd/

unstated

未声明
Meaning
not expressed directly in words; implied or left unsaid
Example
The contract included several unstated expectations.
合同包括了几个未声明的期望。
C1 adjective /ʌnˈskeɪðd/

unscathed

毫发无损
Meaning
Without suffering any injury, damage, or harm.
Example
She escaped from the accident unscathed.
她毫发无损地逃离了事故。
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。
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。
C1 noun /ˈʌndərˌstʌdi/

understudy

替身演员
Meaning
An actor who learns another's role to act as a replacement if needed.
Example
The understudy performed when the lead actor fell ill.
当主角生病时，替身演员上场表演。
B2 noun /ˈɜː.dʒən.si/

Urgency

紧急
Meaning
the quality of requiring immediate action or attention; pressing importance
Example
The urgency of the situation required immediate medical attention.
情况的紧急性要求立即的医疗关注。
C1 verb /ʌpˈruːt/

uproot

拔除
Meaning
To pull something out of the ground; to remove or displace completely.
Example
They uprooted the old tree from the garden.
他们从花园里把老树拔了出来。
C1 verb /ˌʌndərˈvæljuː/

undervalue

低估
Meaning
To assign too low a value or importance to something or someone.
Example
She felt that her boss consistently undervalued her contributions.
她感觉到她的老板总是低估她的贡献。
C1 adjective /ˈʌpərˌmoʊst/

uppermost

最高
Meaning
situated at the highest place or most important
Example
Her family's safety was uppermost in her mind during the crisis.
她在危机期间心里最重要的是家庭的安全。
A2 verb /ʌpˈset/

upset

烦扰
Meaning
to make someone worried, sad, or angry; to disturb
Example
The bad news upset everyone.
坏消息 upset 每个人。
C2 adjective /ʌnˈblʌʃɪŋ/

Unblushing

厚颜无耻的; 放肆的
Meaning
showing no shame or embarrassment; boldly shameless
Example
He told the unblushing lie without any hesitation.
他毫不犹豫地说了那个无耻的谎言。
B2 adjective /ʌnˈwɜːrði/

Unworthy

不配; 没有价值
Meaning
not deserving respect or attention; lacking worth or merit
Example
He felt unworthy of such praise and recognition.
他觉得自己不配得到这样的赞扬和认可。
B2 adjective /ʌnˈbæləns/

Unbalanced

不平衡的; 不稳定的
Meaning
not balanced; lacking stability or equilibrium; mentally unstable
Example
The unbalanced table kept wobbling.
不平衡的桌子摇晃着。
C2 verb /juˈzɜrp/

usurp

篡位
Meaning
to take someone's position of power illegally or by force
Example
The general tried to usurp the king's throne.
将军试图篡夺国王的王位。
C1 adjective /ʌnˈsɪvəlaɪzd/

Uncivilized

未开化的; 野蛮的;
Meaning
not developed in terms of civilization; lacking social organization and culture; barbarous
Example
The explorers encountered an uncivilized tribe deep in the Amazon rainforest.
探险者在亚马逊雨林深处遇到一个未开化的部落。
C1 adjective /ʌnˈkwaɪ.ət/

Unquiet

不安的; 焦虑的; 激动的
Meaning
restless; unable to remain still or quiet; anxious or troubled
Example
She spent an unquiet night worrying about the exam results.
她度过了一个不安的夜晚，担心考试结果。
A1 adjective /juːzd/

used

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

Undue

过度的; 不适当的; 超过必要或适当的
Meaning
excessive; inappropriate; more than is necessary or proper
Example
The teacher complained about undue pressure from parents.
老师抱怨家长施加的过度压力。
C1 verb /ʌnˈsɛtl/

unsettle

扰乱
Meaning
To disturb or make someone feel anxious or uneasy.
Example
The sudden news unsettled the entire community.
突如其来的消息让整个社区感到不安。
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。
C1 noun /ʌnɪmˈpɔːrtəns/

unimportance

不重要
Meaning
the state or quality of being insignificant or not important
Example
He dismissed the issue with a sense of unimportance.
他以無關緊要的態度忽略了這個問題。
B1 adjective /ʌnˈnoʊn/

Unknown

未知
Meaning
not known or identified; unfamiliar
Example
The author of this letter remains unknown.
这封信的作者仍然未知。
B2 noun /ˌʌnəˌveɪləˈbɪləti/

unavailability

不可用性
Meaning
The state of being not available or not accessible.
Example
The unavailability of the manager caused a delay in the project.
经理的不可用性导致了项目的延误。
C2 verb /ʌpˈhiːv/

upheave

抬起
Meaning
to lift or raise something forcefully; to cause to rise suddenly
Example
The workers had to upheave the heavy stone to clear the path.
工人们不得不抬起重石来清理道路。
C2 adjective /ʌnˈtræməld/

untrammeled

无限自由
Meaning
Not restricted or hampered; free and unrestricted.
Example
She enjoyed untrammeled freedom in her new life abroad.
她在国外的新生活中享受着无限自由。
C2 adjective /ˌʌnɪmˈpiːtʃəbl/

unimpeachable

无可指摘
Meaning
Not able to be doubted, questioned, or criticized; completely trustworthy.
Example
She is known for her unimpeachable honesty.
她因其无可指摘的诚实而闻名。
C1 adjective /ˌʌnɪmˈplɔɪəbəl/

unemployable

不适合就业
Meaning
Not able to be employed; lacking the skills or qualities necessary for employment
Example
Due to his criminal record, he was considered unemployable in most companies.
由于他的犯罪记录，他在大多数公司被认为是不适合就业。
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。
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。
C1 adjective /ʌnˈɡɑː.dɪd/

Unguarded

不设防的
Meaning
not protected or defended; careless about revealing private thoughts or information
Example
In an unguarded moment, she revealed her true feelings about the project.
在一个不设防的时刻，她揭示了她对这个项目的真实感受。
C2 noun/verb /ˈʌpˌkæst/

upcast

向上投掷
Meaning
Verb: To cast or throw upward. Noun: Something thrown or directed upward.
Example
The fisherman upcast his net into the air.
渔夫把他的网投向空中。
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。
C1 verb /ˌʌndərˈlaɪ/

underlie

位于...之下
Meaning
to be the hidden cause or basis of something
Example
Strong cultural traditions underlie the community's practices.
强大的文化传统是社区实践的基础。
C1 adjective /ˈʌndərhænd/

underhand

阴险
Meaning
done secretly and dishonestly; deceitful
Example
The politician was accused of using underhand tactics to win the election.
那位政治家被指控使用阴险的手段赢得选举。
B2 noun /juːˈtɪl.ə.ti/

Utility

效用; 益处; 公共服务
Meaning
the state of being useful, profitable, or beneficial; a public service
Example
The utility of solar panels increases with rising electricity costs.
随着电费上涨，太阳能板的效用也在增加。
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。