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。

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。

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。

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。

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。

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 /ˌʌndərˈstændəbl/

understandable

可以理解的

Meaning

Able to be understood; reasonable or justifiable.

Example

Her reaction was understandable given the situation.

考虑到情况，她的反应是可以理解的。

B2 noun /ˈʌpˌkiːp/

up-keep

维护

Meaning

The process or cost of maintaining something in good condition.

Example

The upkeep of the old house is very expensive.

老房子的维护非常昂贵。

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。

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。

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 /ˌʌndərˈhændɪd/

underhanded

阴险

Meaning

acting or done in a dishonest or secret way

Example

They exposed the company's underhanded dealings with its suppliers.

他们揭露了公司与供应商之间的隐秘交易。

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。

C1 noun /ˌʌnbɪˈliːf/

Unbelief

不信

Meaning

lack of religious belief; skepticism or doubt

Example

His unbelief in the supernatural made him a skeptic.

他对超自然的怀疑使他成为了一个怀疑者。

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。

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。

B1 adjective /ʌnˈjuː.ʒu.əl/

Unusual

不寻常; 奇怪;

Meaning

not typical; strange; different from what is normal

Example

She wore an unusual dress to the party.

她穿了一件不寻常的衣服去参加派对。

C2 adjective /ˌʌnəˈsweɪdʒd/

unassuaged

未缓解

Meaning

Not made less intense or relieved; unrelieved.

Example

His grief remained unassuaged despite the passage of time.

他的痛苦尽管时间流逝依然未缓解。

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。

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。

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。

B2 verb /ˈjuːtɪlaɪz/

utilize

利用

Meaning

to make practical or effective use of something

Example

The company aims to utilize solar energy for production.

公司旨在利用太阳能进行生产。

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。

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 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 /ˌʌnɪkˈsɛpʃənəbl/

unexceptionable

无可指摘

Meaning

Not open to objection; acceptable and unobjectionable

Example

His behavior was unexceptionable throughout the event.

他的行为在整个事件中都是无可指摘的。

B1 adjective /ʌnˈnesəseri/

Unnecessary

不必要的；多余的

Meaning

not needed; not required; pointless

Example

The meeting was unnecessary since all decisions were already made.

会议是多余的，因为所有的决定已经做出。

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。

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 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。

C1 noun /ˈʌndərˌɡɑːrmənt/

undergarment

内衣

Meaning

a piece of clothing worn under outer clothes, usually next to the skin

Example

He bought new undergarments for the wedding.

他为婚礼买了新的内衣。

C1 noun /ˈʌp.tɜːn/

upturn

改善

Meaning

An improvement or upward trend in a situation, especially in business or economy.

Example

The company experienced an upturn in sales last quarter.

该公司在上个季度销售情况有所改善。

B2 verb /ʌnˈfəʊld/

unfold

展开或打开

Meaning

to open or spread out something that was folded; to gradually reveal or develop

Example

She unfolded the letter carefully.

她小心地展开了信件。

A2 noun /ʌmˈbrɛlə/

umbrella

伞

Meaning

A device used for protection against rain or sun, typically consisting of a collapsible canopy mounted on a central rod.

Example

She opened her umbrella as it started to rain.

下雨时她打开了她的伞。

B1 preposition, adverb, adjective /ˌʌndərˈniːθ/

underneath

在……下面

Meaning

Located directly below or beneath something

Example

The keys were hidden underneath the pile of papers.

钥匙被隐藏在那堆文件下面。

A2 noun /ˈʌndərweər/

underwear

内衣

Meaning

Clothing worn beneath outer clothes, typically next to the skin.

Example

He bought new underwear for the trip.

他为旅行买了新的内衣。

Meaning

to sell at a lower price than a competitor; to weaken or undermine something

Example

The company tried to undercut its rivals by offering lower prices.

B2 adjective /ʌnˈdɪvaɪdɪd/

Undivided

完整的; 完全的; 不分开或不分裂

Meaning

whole; complete; not separated or split

Example

The team showed undivided attention to the coach's instructions.

团队对教练的指示表现出了完整的注意力。

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。

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 noun /ˌjuːnɪˈfɔːrməti/

Uniformity

一致性；统一性；相同状态

Meaning

the quality of being uniform; consistency or sameness

Example

The uniformity of the design created a pleasing visual effect.

设计的一致性创造了一个吸引人的视觉效果。

C2 adjective /ˌʌn.rɪˈdʒɛn.ər.ət/

unregenerate

顽固

Meaning

Not reformed or showing no signs of change; stubbornly refusing to reform or repent.

Example

He remained an unregenerate opponent of progress.

他仍然是进步的顽固反对者。

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。

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 /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。

C1 adjective /ʌnˈvɔɪst/

unvoiced

未表达

Meaning

not expressed in speech; in phonetics, a sound produced without vocal cord vibration

Example

The student kept her opinion unvoiced during the meeting.

学生在会议期间保持她的意见未表达。

C1 adjective /ˌjuːnɪˈlætərəl/

Unilateral

单方面

Meaning

one-sided; involving only one party

Example

The country made a unilateral decision to withdraw from the treaty.

这个国家做出了单方面的决定，退出了条约。

B2 adjective /ʌnfəˈmɪl.jər/

Unfamiliar

不熟悉的; 陌生的

Meaning

not known or recognized; strange

Example

The city was unfamiliar to me since I had never been there before.

这座城市对我来说很陌生，因为我以前从未去过那里。

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。

C1 adjective /ʌnˈtaɪmli/

Untimely

不合时宜

Meaning

happening at an inappropriate or inconvenient time; premature

Example

His untimely death at the age of thirty shocked everyone.

他的过早死亡在30岁时震惊了所有人。

B2 adjective /juːˈnæn.ɪ.məs/

Unanimous

一致的

Meaning

fully in agreement; shared by all

Example

The committee reached a unanimous decision.

委员会达成了一致的决定。

C2 adjective /ʌnˈmɪtɪɡeɪtɪd/

unmitigated

完全

Meaning

absolute; not lessened or moderated

Example

The meeting was an unmitigated disaster.

会议是一次完全的灾难。

C1 adjective /ˌʌnɪˈkwɪvəkəl/

unequivocal

明确

Meaning

Leaving no doubt; clear and unambiguous

Example

She gave an unequivocal answer to the question.

她对问题给出了明确的回答。

C1 noun /ˌʌnriˈælɪti/

unreality

非现实

Meaning

the state or quality of being unreal; lack of reality or truth

Example

The dreamlike setting gave the story a sense of unreality.

这种梦幻的场景让故事充满了非现实感。

B2 verb /ˌʌndərˈskɔːr/

underscore

强调

Meaning

to emphasize or highlight something

Example

The incident underscored the need for better safety measures.

这起事件突显了更好安全措施的必要性。

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。

B1 noun /ˈjuːs.fəl.nəs/

Usefulness

有用性

Meaning

the quality of being useful; practical value or helpfulness

Example

The usefulness of this tool became apparent during the project.

这个工具的有用性在项目过程中变得显而易见。

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 adjective /ʌnˈwel.kəm/

Unwelcome

不受欢迎的; 不想要的; 不邀请的

Meaning

not wanted or accepted; not invited or pleasant

Example

The unwelcome news ruined their vacation plans.

不受欢迎的消息破坏了他们的度假计划。

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。

C1 adjective /ˌʌnkɒnstɪˈtuːʃənəl/

Unconstitutional

违宪的

Meaning

not in accordance with a political constitution; violating constitutional principles

Example

The court declared the new law unconstitutional.

法院宣布这项新法律违宪。

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。

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。

B1 adjective /ˈʌpər/

upper

上层

Meaning

higher in position or rank

Example

The upper floor of the building is under renovation.

建筑物的上层正在翻修。

C2 noun /ˈjuːzjuːfrʌkt/

usufruct

使用权

Meaning

The legal right to use and enjoy the benefits of someone else’s property without owning it.

Example

The tenant had the usufruct of the land but not its ownership.

租户有权使用这片土地，但没有所有权。

B2 adjective /ʌnˈhɜːd/

Unheard

未听到的; 未知的

Meaning

not heard or listened to; not given a hearing; unknown or unfamiliar

Example

His complaints went unheard by the management.

他的投诉没有被管理层听到。

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。

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 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 /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。

B1 adjective /juːˈnaɪtɪd/

United

联合的; 一致的; 团结的

Meaning

joined together for a common purpose; in agreement

Example

The team was united in their goal to win.

团队在他们的目标上达成了统一。

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。

C1 adjective /ʌnˈfɔːltərɪŋ/

unfaltering

坚定不移

Meaning

Steady and resolute; not weakening or hesitating

Example

She continued with unfaltering determination.

她以坚定不移的决心继续前进。

C2 adjective /ˌʌnəˈʃʊəd/

unassured

不确定的

Meaning

Lacking confidence or certainty.

Example

She gave an unassured answer during the interview.

她在面试中给出了一个不确定的答案。

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。

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。

C1 verb /ʌnˈroʊl/

unroll

展开

Meaning

to open something that is rolled up; to spread out gradually

Example

She unrolled the map on the table to find the route.

她把地图在桌子上展开来寻找路线。

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。

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 /ˌʌnɪnˈfɔːrmd/

uninformed

不了解情况的

Meaning

lacking knowledge or awareness about a particular subject; not educated or informed

Example

The decision was made by an uninformed committee.

这个决定是由一个不了解情况的委员会做出的。

B2 adjective /ʌnhaɪˈdʒiːnɪk/

Unhygienic

不卫生的；缺乏适当的卫生

Meaning

not clean; lacking proper sanitation

Example

The restaurant was closed due to unhygienic conditions in the kitchen.

由于厨房不卫生的条件，餐厅被关闭。

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。

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。

B1 adjective /ʌnˈlaɪk/

Unlike

不同的; 不相似的

Meaning

different from; not similar to

Example

Unlike his brother, he prefers quiet activities.

与他哥哥不同，他喜欢安静的活动。

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。

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。

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。

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。