indubitable
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C2 adjective /ɪnˈdjuːbɪtəbl/

indubitable

无可置疑
Meaning
Impossible to doubt; unquestionable.
Example
It is indubitable that hard work leads to success.
毫无疑问，努力工作会带来成功。
C1 adjective /ɪmˈpɜːmiəbl/

impermeable

不透水的
Meaning
Not allowing fluid or gas to pass through.
Example
The container is made of impermeable plastic.
这个容器是由不透水的塑料制成的。
C2 noun /ˈɪɡ.nəˌmɪn.i/

ignominy

耻辱
Meaning
Public shame, disgrace, or dishonor.
Example
He lived the rest of his life in ignominy after the scandal.
他在丑闻后余生都活在耻辱中。
C1 adjective /ɪnˈɔːdəbl/

inaudible

听不见的
Meaning
Unable to be heard.
Example
Her voice was almost inaudible over the noise.
她的声音几乎在噪音中听不见。
C2 noun /ɪmˈprɑːvɪdəns/

improvidence

缺乏远见
Meaning
Lack of foresight or care for future needs.
Example
His improvidence led to financial difficulties.
他的缺乏远见导致了财务困难。
B2 adjective /ˈɪn.tɪ.mət/

Intimate

亲密的; 私人的; 详细的知识
Meaning
close in friendship; private and personal; detailed knowledge
Example
They have an intimate friendship that has lasted for decades.
他们有一段持续数十年的亲密友谊。
C1 noun /ˈɪrɪtənt/

irritant

刺激物
Meaning
something that causes irritation or discomfort
Example
Dust is a common irritant for people with allergies.
灰尘是过敏者常见的刺激物。
C1 noun /ˌɪnsəˈfɪʃənsi/

insufficiency

不足
Meaning
The state of not being enough or not being adequate.
Example
The project failed due to the insufficiency of funds.
由于资金不足，项目失败了。
C1 noun /ˈɪnkwest/

inquest

调查
Meaning
A legal or official inquiry, especially into the cause of a death.
Example
The inquest revealed the cause of the accident.
调查揭示了事故的原因。
C1 adjective /ˌɪnɔːrˈɡænɪk/

inorganic

无机的
Meaning
relating to substances that are not derived from living organisms; lacking organic structure or growth
Example
Inorganic compounds are commonly studied in chemistry labs.
无机化合物是化学的重要部分。
B2 adjective /ˌɪnkənˈviːniənt/

Inconvenient

不便的; 难堪的; 麻烦的
Meaning
causing trouble, difficulties, or discomfort; awkward; troublesome
Example
The broken elevator made it inconvenient to reach the top floor.
坏掉的电梯使得到达顶楼变得不方便。
C1 noun /ɪmˈpjʊərəti/

impurity

杂质
Meaning
the state of being unclean or contaminated; a substance that makes something impure
Example
The scientist removed every impurity from the water sample.
科学家去除了水样中的所有杂质。
C2 adjective /ˌɪnɪˈsɛnʃəl/

inessential

非必要的
Meaning
not necessary or important; not essential
Example
The report removes all inessential details to stay focused.
报告删除了所有非必要的细节以保持重点。
C2 noun /ˌɪntərˈrɛɡnəm/

interregnum

过渡期
Meaning
A period between rulers or governments when normal leadership is suspended.
Example
The country faced instability during the interregnum after the king’s death.
在国王去世后的过渡期，该国经历了不稳定。
B2 noun ˌɪn.təˈven.ʃən

intervention

干预
Meaning
The action or process of intervening; involvement in a situation to improve or help it.
Example
The intervention of the UN was crucial in resolving the conflict.
联合国的干预对解决冲突至关重要。
C1 adjective ɪˈneɪt

Innate

与生俱来的或自然的
Meaning
Existing from birth or natural
Example
She has an innate talent for music.
她有天生的音乐才华。
B2 noun /ˌɪntəˈrʌpʃən/

interruption

中断
Meaning
the act of stopping or breaking the continuity of something; a pause caused by an external action
Example
The meeting was delayed due to an unexpected interruption.
会议因为一次意外的中断而被推迟。
B2 adjective /ɪmˈpɜːrfɪkt/

imperfect

不完美
Meaning
Not perfect; having faults or flaws.
Example
The painting was beautiful despite being imperfect.
这幅画很美，尽管它不完美。
C1 adjective /ɪnˈvæljʊəbl/

invaluable

无价
Meaning
Extremely useful or indispensable.
Example
Her advice proved invaluable to my success.
她的建议对我的成功起到了无可估量的作用。
C2 noun /aɪər/

ire

愤怒, 激怒
Meaning
intense anger or rage
Example
The new policy provoked the ire of the employees.
新政策激怒了员工。
C2 verb /ɪnˈdɛmnɪfaɪ/

indemnify

Meaning
to compensate someone for harm or loss; to secure against future damage or cost
Example
The insurance company agreed to indemnify the client for the damages.
C1 adjective /ˌɪndɪˈskraɪbəbəl/

Indescribable

无法形容
Meaning
impossible to describe or express in words; beyond description
Example
The beauty of the sunset was indescribable.
夕阳的美丽是无法形容的。
C1 adjective ˌɪn.təˈmɪt.ənt

intermittent

间歇的
Meaning
Happening irregularly, not continuously.
Example
The rain was intermittent throughout the day.
雨整天都间歇不断。
C2 noun /ˌɪntərˈsɛsər/

intercessor

调解人
Meaning
a person who intervenes or pleads on behalf of another
Example
He acted as an intercessor to resolve the conflict between the two families.
他作为调解人解决了两个家庭之间的冲突。
C2 verb /ˌɪmpɔːrˈtuːn/

importune

反复请求
Meaning
To ask someone persistently or pressingly for something
Example
The child importuned his mother for a new toy.
孩子反复请求母亲给他买一个新玩具。
C2 noun /ɪnˈtɜːrstɪs/

interstice

缝隙
Meaning
a small space that lies between things
Example
Light filtered through the narrow interstices of the wall.
光线透过墙壁的狭窄缝隙照射进来。
C2 verb /ˌɪn.trəˈmɪt/

intromit

引入
Meaning
To insert or introduce something into a place or body.
Example
The doctor carefully intromitted the instrument into the wound.
医生小心地将仪器引入伤口。
C1 adjective /ˌɪrɪˈprɛsəbl̩/

irrepressible

不可抑制的
Meaning
Impossible to control or restrain.
Example
She had an irrepressible urge to laugh during the speech.
她在演讲中无法掩饰自己无法抑制的笑意。
A1 noun /ˈaɪs kriːm/

Ice-cream

冰淇淋
Meaning
a frozen sweet dessert made from dairy products, usually served cold
Example
Children love to eat ice-cream on hot summer days.
孩子们喜欢在炎热的夏季日子里吃冰淇淋。
C2 noun /ˌɪmpjuˈteɪʃən/

imputation

指控
Meaning
an accusation or attribution of blame
Example
The politician denied the imputation of corruption.
政治家否认了腐败的指控。
C1 adjective /ɪnˈtɒl.ər.ə.bəl/

Intolerable

难以忍受的
Meaning
unable to be endured; extremely unpleasant or painful
Example
The noise from the construction site was intolerable.
建筑工地的噪音让人无法忍受。
C1 verb /ˈɪmplɪˌkeɪt/

implicate

牵涉
Meaning
To show someone’s involvement in a crime or wrongdoing.
Example
The evidence implicated several officials in the scandal.
证据揭示了几名官员在丑闻中的牵涉。
C1 noun /ˈɪn.fən.tri/

Infantry

步兵
Meaning
soldiers marching or fighting on foot; foot soldiers collectively
Example
The infantry advanced across the battlefield on foot.
步兵在战场上走路前进。
B2 noun ˌɪnɪˈkwɒlɪti

inequality

不平等
Meaning
Difference in size, degree, circumstances, etc.; lack of equality.
Example
The theme of inequality is prominent throughout the story.
不平等的主题在整个故事中是显著的。
B1 verb /ˈɪndɪkeɪt/

indicate

指示
Meaning
to point out; to show or suggest; to be a sign of
Example
The red light indicates that you should stop.
红灯表示你应该停下来。
C2 verb /ɪmˈpeɪl/

impale

刺穿
Meaning
to pierce or fix something with a sharp object
Example
The knight was impaled by the enemy’s spear.
骑士被敌人的长矛刺穿。
B2 verb ˈɪmplɪmentɪd

implemented

实施
Meaning
Put a decision or plan into effect; carried out or executed.
Example
The master plans were partially implemented.
主要计划已部分实施。
C2 verb ˈɪnʌndeɪt

inundate

淹没, 用事情或人淹没某人或某物
Meaning
To flood; overwhelm someone or something with things or people to be dealt with
Example
The company was inundated with requests after the advertisement.
广告后，公司被大量请求淹没。
C1 adverb /ɪnˈdɛfɪnətli/

indefinitely

无限期
Meaning
for an unlimited or unspecified period of time
Example
The project has been postponed indefinitely.
该项目已无限期推迟。
B2 noun /ˈaɪrəni/

irony

讽刺
Meaning
a situation that is strange or amusing because it is the opposite of what is expected; the use of words to convey the opposite meaning
Example
The irony of the situation was that the winner forgot his own prize.
这件事的讽刺在于，获胜者忘记了自己的奖品。
A1 noun /ˌɪnfərˈmeɪʃən/

information

信息
Meaning
Facts or knowledge provided or learned about something.
Example
The website provides useful information about travel destinations.
该网站提供有关旅游目的地的有用信息。
C2 noun /aɪˈoʊtə/

iota

极小的数量
Meaning
An extremely small amount.
Example
He did not show an iota of fear.
他一点儿恐惧都没表现出来。
C2 adjective /ɪnˈvʌlnərəbl/

invulnerable

无敌
Meaning
Impossible to harm, damage, or defeat.
Example
The fortress was thought to be invulnerable to attack.
堡垒被认为无法受到攻击。
C2 noun /ɪnˈvaɪtər/

invitor

邀请者
Meaning
a person who invites someone to an event, meeting, or place
Example
The invitor greeted all the guests warmly at the entrance.
邀请者在入口处热情地欢迎了客人。
B2 noun ɪnˌdʌstrɪəlaɪˈzeɪʃən

industrialization

工业化
Meaning
The development of industries in a country or region on a wide scale.
Example
Industrialization changed the global economy dramatically.
工业化显著改变了全球经济。
C2 adjective /aɪˈdɒlətrəs/

idolatrous

偶像崇拜者
Meaning
Excessively admiring or worshipping someone or something as an idol.
Example
The king was criticized for his idolatrous devotion to wealth.
国王因其对财富的偶像崇拜而受到批评。
C2 adjective /ˌɪndɪˈvɜːrtɪbəl/

indivertible

Meaning
Not able to be turned aside or diverted.
Example
The judge's indivertible attention was on the case.
C1 noun /ˈɪmɪnəns/

imminence

即将发生，临近状态
Meaning
the state of being about to happen
Example
The imminence of the storm forced people to take shelter.
风暴的临近使人们不得不寻找庇护所。
B2 verb aɪˈdɛntɪfaɪd

identified

已识别
Meaning
To recognize or establish who or what someone or something is.
Example
The root causes of the issue need to be identified.
问题的根本原因需要被识别。
B1 noun ɪˈnɪʃətɪvz

initiatives

倡议
Meaning
Actions or strategies designed to resolve a difficulty or improve a situation; programs or projects.
Example
Community initiatives benefit underprivileged groups.
社区倡议惠及贫困群体。
C2 adjective /ˌɪrɪˈlɪdʒəs/

irreligious

不信教的
Meaning
Indifferent or hostile to religion
Example
Some people in the community consider him irreligious because he never attends religious services.
社区中的一些人认为他不信教，因为他从不参加宗教服务。
C1 adjective /ɪnˈkrɛdjələs/

incredulous

Meaning
unwilling or unable to believe something
Example
He gave her an incredulous look when she claimed she could fly.
C2 adjective /ˌɪrɪˈdjuːsəbl/

irreducible

不可约的
Meaning
impossible to reduce or simplify further
Example
The fraction 3/7 is irreducible.
分数 3/7 是不可约的。
C1 adjective /ˌɪrɪˈvɜːrsəbl/

irreversible

不可逆的
Meaning
Not able to be undone, changed, or reversed.
Example
The damage caused by the fire was irreversible.
火灾造成的损失是不可逆的。
C1 noun /ˈɪŋ.krə.mənt/

Increment

增加
Meaning
an increase or addition, especially one of a series on a fixed scale; a regular increase in salary
Example
He received an annual increment of five percent in his salary this year.
他今年获得了五个百分点的年终增加。
B2 noun /ˌɪntərˈsɛkʃən/

intersection

交叉口
Meaning
a point where two or more things intersect, especially a road or path
Example
The intersection of Main Street and 5th Avenue is always busy.
主街和第五大道的交叉口总是很忙。
C1 noun/verb /ˈɪnsɛns/

incense

香火 / 激怒
Meaning
a substance burned for its sweet smell (noun); to make very angry (verb)
Example
The smell of incense filled the temple, but his rude words incensed her.
香火的气味充满了寺庙，但他粗鲁的话让她非常生气。
B1 noun ɪnˈven.ʃən

invention

发明
Meaning
The action of inventing something, typically a process or device.
Example
The invention revolutionized communication.
这个发明彻底改变了通信。
C2 noun /ˌɪnkənˈɡruːəti/

incongruity

不一致
Meaning
The state of being inconsistent or out of place.
Example
The incongruity of his cheerful mood during the funeral shocked everyone.
在葬礼上，他愉快的心情与情境的不一致让所有人都震惊了。
A1 pronoun /ɪts/

its

它的
Meaning
Belonging to or associated with a thing previously mentioned.
Example
The company changed its logo last year.
公司去年更改了它的标志。
C1 verb /ɪmˈplɔːr/

implore

Meaning
To beg someone earnestly or desperately to do something.
Example
She implored him to stay with her.
C2 adjective /ˌɪnɔːˈspɪʃəs/

Inauspicious

不吉利
Meaning
unlucky; showing signs that future success is unlikely; unfavorable
Example
The dark clouds seemed inauspicious for the wedding.
黑云似乎对婚礼不吉利。
B2 noun /ˌɪnstəˈbɪləti/

instability

不稳定
Meaning
lack of stability or balance; tendency to change, fail, or collapse easily
Example
Political instability has slowed economic growth in the region.
政治不稳定减缓了该地区的经济增长。
A1 preposition /ɪn ˈfrʌnt əv/

in front of

在……前面
Meaning
positioned before or ahead of something; facing or located at the forward side of a person or object
Example
She stood in front of the building.
她站在建筑物前面。
C2 adjective /ˈɪnmoʊst/

inmost

最深的
Meaning
Situated at the very heart or deepest part; most private or secret.
Example
She revealed her inmost thoughts to her closest friend.
她向她最亲密的朋友透露了她最深的想法。
C1 adjective /ɪnˈhɛrənt/

inherent

固有的
Meaning
Existing in something as a natural, permanent, or essential quality.
Example
There are inherent risks in extreme sports.
极限运动中存在固有的风险。
C1 adjective /ɪnˈveə.ri.ə.bəl/

Invariable

不变的；恒定的；始终相同的
Meaning
never changing; constant; always the same
Example
His invariable routine includes morning exercise and coffee.
他的恒定日常包括早晨锻炼和咖啡。
C2 adjective /ɪmˌpɜːrˈsweɪdəbl/

impersuadable

难以说服
Meaning
not able to be convinced or persuaded
Example
She remained impersuadable despite all our arguments.
尽管我们的所有论点，她仍然难以说服。
C1 noun /ˌɪnkjʊˈbeɪʃən/

incubation

将蛋、细胞或生物置于适宜的环境条件中以促进其发展的过程
Meaning
the process of keeping eggs, cells, or organisms in the right conditions for development
Example
The incubation of the eggs lasted for three weeks.
蛋的孵化持续了三周。
C1 adjective /ɪˈluː.sɪv/

Illusive

虚幻的; 看似存在但不真实; 欺骗性的
Meaning
deceptive; appearing to exist but not real; misleading
Example
The promise of easy money proved to be illusive and misleading.
轻松赚钱的承诺证明是虚幻和欺骗性的。
C2 verb /ɪˈniː.bri.eɪt/

inebriate

Meaning
to intoxicate; to make someone drunk
Example
The strong wine was enough to inebriate even the most experienced drinker.
C1 adjective /ˌɪndɪˈfɛnsəbl̩/

indefensible

无法辩护
Meaning
not able to be protected or justified
Example
The minister’s remarks were considered indefensible by the public.
部长的言论被公众视为无法辩护。
B2 verb /ˈaɪ.sə.leɪt/

isolate

孤立
Meaning
To separate something or someone from others.
Example
Doctors tried to isolate the patient to prevent the spread of infection.
医生试图将病人隔离，以防止感染传播。
C2 adjective /ɪnˈɛstɪməbl/

inestimable

无法估量的
Meaning
Too great or valuable to be measured or estimated.
Example
Her contribution to the project was of inestimable value.
她对项目的贡献具有无法估量的价值。
B2 verb /ɪnˈdjuːs/

induce

引起
Meaning
to cause or persuade someone to do something; to bring about a result
Example
The doctor induced sleep with a mild sedative.
医生用轻度镇静剂引起了睡眠。
B2 adjective /ɪnˈtɛnsɪv/

intensive

强化
Meaning
Involving a lot of effort, energy, or concentration in a short period of time.
Example
She attended an intensive English course before moving abroad.
她在出国之前参加了一个强化的英语课程。
C2 adjective /ɪɡˈnoʊ.bəl/

Ignoble

卑鄙; 可耻; 不光彩
Meaning
dishonorable; not noble in character; base or mean
Example
His ignoble actions betrayed his friends' trust.
他卑鄙的行为背叛了朋友的信任。
B2 noun /ɪnˈkwaɪəri/ or /ˈɪnkwəri/

inquiry

调查 / 查询
Meaning
An act of asking for information; an investigation into something.
Example
The committee launched an inquiry into the financial irregularities.
委员会启动了对金融不规范行为的调查。
C1 adjective /ɪnˈsʌf.ər.ə.bəl/

insufferable

无法忍受
Meaning
Too extreme to bear; intolerable.
Example
The heat during the summer was insufferable.
夏天的炎热是无法忍受的。
C1 noun /ɪnˈkɜːrʒən/

incursion

入侵
Meaning
A sudden attack or invasion into a place or territory.
Example
The army repelled the enemy incursion at the border.
军队在边境击退了敌人的入侵。
A2 noun/adjective /ˌɪndɪˈvɪdʒuəl/

individual

个体
Meaning
A single human being as distinct from a group; relating to one person.
Example
Each individual has the right to freedom of speech.
每个个体都有言论自由的权利。
C2 adjective /ˌɪndaɪˈdʒestəbəl/

Indigestible

难以消化; 难以处理
Meaning
difficult or impossible to digest; hard to process in the stomach
Example
The old bread became hard and indigestible.
老面包变得坚硬且难以消化。
C1 adjective /ˌɪn.ɪˈfɛk.tʃu.əl/

ineffectual

无效
Meaning
Not producing any or the desired effect; lacking the ability or qualities to achieve a purpose.
Example
The manager’s ineffectual leadership caused the team to lose motivation.
经理无效的领导导致团队失去了动力。
C1 verb /ɪmˈpɒvərɪʃ/

impoverish

使贫穷
Meaning
To make someone poor or reduce the quality or richness of something.
Example
The long war impoverished the entire nation.
漫长的战争使整个国家贫困。
C2 noun /ɪˈluːmɪnənt/

illuminant

光源
Meaning
A substance or device that produces light.
Example
The lamp acted as an illuminant in the dark cave.
这盏灯在黑暗的洞穴中充当了光源。
A1 adjective /ˈɪntrəstɪŋ/ or /ˈɪntəˌrɛstɪŋ/

interesting

有趣的
Meaning
Arousing curiosity or attention; holding one’s interest.
Example
The documentary about space was very interesting.
关于太空的纪录片非常有趣。
B2 verb /ɪnˈstrʌkt/

instruct

指示
Meaning
to teach; to give directions
Example
The teacher instructed the students carefully.
老师仔细地指示了学生。
C1 adjective /ɪnˈtændʒəbl/

intangible

无形的
Meaning
Unable to be touched or grasped; not having a physical presence.
Example
Trust is an intangible quality in relationships.
信任是关系中一种无形的品质。
C2 noun /ˌɪnjuːˈɛndəʊ/

innuendo

暗示
Meaning
An allusive or oblique remark or hint, typically a suggestive or disparaging one.
Example
The manager's innuendo was directed towards his competitor.
经理的暗示是针对他的竞争对手的。
C2 adjective /ˌɪnɪkˈspiːdiənt/

inexpedient

不合适
Meaning
Not advisable, suitable, or practical in the circumstances.
Example
It would be inexpedient to invest without proper research.
在没有适当研究的情况下进行投资是不合适的。
B1 adjective /ɪnˈfɔːrməl/

Informal

非正式的; 放松的; 随意的
Meaning
relaxed and friendly; not official or ceremonial; casual
Example
The meeting was informal and relaxed.
会议是非正式的且轻松的。
C2 adjective /ɪmˈplækəbl/

implacable

不可调和
Meaning
unable to be appeased, calmed, or pacified
Example
The soldiers faced an implacable enemy who refused to surrender.
士兵们面对着一个不可调和的敌人，他拒绝投降。
C1 verb ɪmˈbjuː

Imbue

将某个想法或感觉深深融入某人的心灵
Meaning
Mixing some idea or feeling deeply into someone's mind
Example
The teacher tried to imbue students with a love for learning.
老师试图将对学习的热爱注入学生心中。
B2 noun /ɪnˈventər/

inventor

发明家
Meaning
a person who creates or designs something new, especially a device, method, or process
Example
The inventor patented her new medical device.
这位发明家为她的新医疗设备申请了专利。
C1 adjective /ˈɪrɪtəbl/

irritable

Meaning
easily annoyed or made angry
Example
She became irritable after working long hours without rest.
C2 verb /ɪmˈpjuːt/

impute

归因于
Meaning
to attribute a fault or responsibility to someone
Example
They imputed the company's success to good leadership.
他们将公司的成功归功于出色的领导力。
B2 noun ɪnˈtɛɡrɪti

integrity

完整性
Meaning
The quality of being honest and having strong moral principles; moral uprightness.
Example
Teachers' integrity fosters a positive learning environment.
教师的完整性促进了积极的学习环境。
C2 noun /ɪnˈsɪɡniə/

insignia

徽章
Meaning
A badge or symbol that shows rank, position, or membership.
Example
The soldier proudly wore the insignia of his regiment.
士兵自豪地佩戴着他团的徽章。
C2 adjective /ɪmˈpɒndərəbl̩/

imponderable

无法估量
Meaning
Something difficult or impossible to estimate, assess, or understand
Example
The outcome of the election depends on many imponderable factors.
选举结果取决于许多无法估量的因素。
C2 noun /ɪnˈtɜːrmənt/

interment

埋葬
Meaning
The act of burying a dead body in a grave or tomb.
Example
The interment took place at the family cemetery.
埋葬仪式在家庭墓地举行。
C2 adjective /ˌɪmpəˈmɪsəbl/

impermissible

不允许的
Meaning
Not permitted or allowed.
Example
Such behavior is impermissible in the workplace.
这种行为在工作场所是不允许的。
C2 verb /ɪˈnjʊər/

inure

习惯
Meaning
To become accustomed to something, especially something unpleasant.
Example
Soldiers quickly became inured to the harsh conditions.
士兵们迅速适应了严酷的条件。
B2 adjective /ˈɪrɪteɪtɪd/

irritated

恼火的
Meaning
feeling annoyed or impatient; having inflamed or sore physical condition
Example
She felt irritated by the constant noise outside her window.
窗外持续的噪音让她感到恼火。
C1 verb /ɪnˈstɪl/

instill

灌输
Meaning
to gradually but firmly establish an idea, attitude, or habit in someone's mind
Example
Parents try to instill good values in their children.
父母试图在孩子们的心中灌输好的价值观。
C2 verb /ɪˈluːmɪn/

illumine

照亮
Meaning
to light up or make clear
Example
The rising sun illumined the mountain peaks.
初升的太阳照亮了山峰。
B2 noun /ˈɪnstɪŋkt/

instinct

本能
Meaning
A natural way of behaving or reacting that does not require learning.
Example
Birds build nests by instinct.
鸟类本能地筑巢。
B2 noun ɪˈmjuː.nɪ.ti

immunity

免疫力
Meaning
The ability of an organism to resist a particular infection or toxin by the action of specific antibodies.
Example
A strong immunity protects against infections.
强大的免疫力可以防止感染。
C1 noun /ɪmˈpɛd.ɪ.mənt/

impediment

障碍
Meaning
A hindrance or obstruction in doing something; something that prevents progress.
Example
Lack of funds is a major impediment to the project.
资金不足是项目的主要障碍。
C2 noun /ˈɪkθiəˌsɔːrz/

ichthyosaurs

鱼龙（已灭绝的海洋爬行动物）
Meaning
Extinct marine reptiles that resembled fish and dolphins, dominant during the Mesozoic era.
Example
Ichthyosaurs were swift predators of the ancient seas.
鱼龙是古代海洋的迅猛掠食者。
C1 noun /ˈaɪsətəʊp/

isotope

同位素
Meaning
Atoms of the same element with equal number of protons but different numbers of neutrons.
Example
Carbon-14 is a radioactive isotope used in dating fossils.
碳-14 是一种放射性同位素，用于化石的年代测定。
C1 adjective ˌɪn.krəˈmen.təl

incremental

增量
Meaning
Relating to or denoting an increase or addition, especially one of a series on a fixed scale; proceeding in small stages.
Example
Incremental changes ensure sustainability.
增量变化确保可持续性。
C2 adjective /ˌɪnˌɑːpərˈtuːn/

inopportune

不合时宜的时刻
Meaning
Happening at a bad or inconvenient time.
Example
His call came at the most inopportune moment.
他的电话在最不合时宜的时刻打来。
C1 adjective /ɪˈlʌstriəs/

illustrious

著名
Meaning
Well known, respected, and admired for past achievements.
Example
She had an illustrious career in medicine.
她在医学界有着著名的事业。
C1 adjective /ɪˈmuː.və.bəl/

immovable

不可移动
Meaning
Not able to be moved; fixed in position.
Example
Immovable barriers prevent change.
不可移动的障碍阻止了改变。
C2 adjective /ɪmˈpɪəriəs/

imperious

专横
Meaning
Arrogantly domineering or overbearing.
Example
Her imperious tone made it hard for others to argue.
她那种专横的语气让其他人很难反驳。
C2 adjective /ɪˈnɪm.ɪ.tə.bəl/

inimitable

无可比拟
Meaning
So good or unusual as to be impossible to copy; unique.
Example
His inimitable writing style made him a literary legend.
他那无可比拟的写作风格使他成为了文学传奇。
C1 noun ˌɪn.toʊˈneɪ.ʃən

intonation

语调
Meaning
The rise and fall of tone in speech and pronunciation.
Example
Proper intonation enhances the clarity of a speech.
正确的语调提高演讲的清晰度。
C1 verb ɪˈmɜːrs

immerse

沉浸
Meaning
To involve oneself deeply in a particular activity or interest; to surround completely.
Example
Immerse yourself in the new language.
沉浸在新的语言中。
B1 verb /ɪnˈsɪst/

insist

坚持
Meaning
to demand firmly; to state persistently
Example
He insisted on paying the bill.
他坚持要付账单。
C1 adjective /ɪnˈtrɛpɪd/

intrepid

无畏
Meaning
fearless and adventurous, often used humorously
Example
The intrepid traveler explored the jungle alone.
那个无畏的旅行者独自探险了丛林。
B2 adjective ɪˈmɜː.sɪv

immersive

沉浸式
Meaning
Providing, involving, or characterized by deep absorption or immersion in something.
Example
Virtual reality creates an immersive learning environment.
虚拟现实创造了一个沉浸式学习环境。