reaction

/riˈækʃn/ (bre, ipa) · /riˈækʃn/ (ame, ipa) · /rē-ˈak-shən/ (ame, mw)

reaction — 名詞

  • reactionsingular
  • reactionsplural

1. your way of behaving, feeling, or acting that follows directly from an event or

1.名詞B1
釋義

反應

因某事物而產生的行為或感受

your way of behaving, feeling, or acting that follows directly from an event or situation — for example, feeling shock after hearing bad news, or clapping when a performance finishes.

例句

Tamar's immediate reaction to the job offer was one of surprise and delight.

Tamar 對這份工作邀約的第一反應是驚訝與喜悅。

immediate reaction + to + noun phrase

The city council's reaction to the housing shortage was to approve new building permits.

市議會對住房短缺的反應，是核准新的建照。

reaction + to + noun + verb pattern

同義詞
  • response

    more deliberate and often implies thought; 'reaction' can be more automatic

  • reply

    limited to words or written answers, not feelings or actions

  • feedback

    evaluative reaction given to help someone improve

反義詞

文法句型

reaction + to + noun/pronoun/gerund

in reaction + to + noun

as a reaction + to + noun

there + be + a reaction + to + noun

用法筆記

Often followed by 'to' to indicate the cause. The verb pattern varies: a reaction can be a feeling, a word, or an action.

常見錯誤

❌What was your reaction about the movie?
✅What was your reaction to the movie?
💡use 'to', not 'about', after 'reaction'.
❌I had a reaction of anger
✅My reaction was one of anger' or 'I reacted with anger
💡'reaction of' is rare and unnatural in most contexts.

2. a physical change in the body that shows you have a negative sensitivity to a su

2.名詞B2
釋義

過敏

身體對藥物或食物產生的不良反應

a physical change in the body that shows you have a negative sensitivity to a substance such as food, medicine, or pollen — examples include rashes, swelling, breathing difficulty, or an itchy feeling after eating something you are allergic to.

例句

Marta had a severe allergic reaction to the shellfish and needed urgent medical attention.

Marta 對貝類產生嚴重的過敏反應，需要緊急醫療處理。

allergic reaction + to + substance — medical collocation

Ravindra developed a red, itchy skin reaction three days after starting the penicillin treatment.

Ravindra 在開始使用青黴素治療的第三天，皮膚出現又紅又癢的過敏反應。

同義詞
  • allergy

    the long-term condition, not the individual event; 'reaction' is a single episode

  • response

    neutral; 'reaction' in this sense implies negative sensitivity

  • side effect

    broader — includes any unintended effect, not just allergic ones

文法句型

reaction + to + noun (substance/formula)

have + a + reaction + to + noun

experience + a + reaction

用法筆記

Medical context. 'Reaction' can be mild (slight rash) or severe (anaphylaxis). 'Adverse reaction' is a formal medical term for any unwanted drug effect, not just allergy.

常見錯誤

❌I had an allergy reaction to peanuts
✅I had an allergic reaction to peanuts
💡the adjective is 'allergic', not 'allergy'.
❌He reacted to the medicine' (when a bodily reaction is meant)
✅He had a reaction to the medicine
💡'have a reaction' is the natural noun form.

3. the speed with which someone can act or respond when something unexpected happen

3.名詞B2
釋義

反應速度

迅速應對突發狀況的能力

the speed with which someone can act or respond when something unexpected happens — used especially about physical reflexes, such as a driver braking to avoid a crash or a goalkeeper saving a shot.

例句

The driver's quick reaction prevented a serious accident on the icy highway.

司機反應迅速，在結冰的高速公路上避免了一場嚴重車禍。

quick reaction — adjective + reaction describing speed

A good goalkeeper needs excellent reactions to stop a fast-moving penalty kick.

優秀的守門員需要極佳的反應速度，才能擋住快速飛來的罰球。

同義詞
  • reflexes

    more specific to automatic physical responses; 'reactions' can include conscious decisions

  • quickness

    general speed of response, less specific than 'reactions'

文法句型

reaction + time(s)

have + adjective + reactions

quick/fast/good reactions

用法筆記

In this sense 'reactions' (plural) is common in British English ('She has good reactions'). 'Reaction time' (singular) is the standard term in sports science and psychology.

常見錯誤

❌He has a very fast reaction' (meaning physical reflexes)
✅He has very fast reactions
💡use the plural when talking about physical response ability.

4. [chemistry] a change where substances interact and turn into new materials — for

4.名詞B2
釋義

化學反應

物質間相互作用產生變化的過程

[chemistry] a change where substances interact and turn into new materials — for example, iron rusting when it meets oxygen and water, or an acid and a base combining to create salt and water.

例句

The students observed a chemical reaction when they mixed vinegar with baking soda.

學生將醋與小蘇打混合時，觀察到了一種化學反應。

chemical reaction — scientific collocation

Iron powder meeting oxygen in a hand warmer pack triggers a reaction that releases enough heat to warm your palms.

暖暖包中的鐵粉接觸氧氣時會引發化學反應，釋放出足以溫暖手掌的熱能。

released during + reaction — prepositional common pattern

同義詞

文法句型

chemical + reaction

set off / trigger + a + reaction

reaction + between + noun + and + noun

用法筆記

General term for all chemical transformations. 'Chain reaction' describes a sequence where each step triggers the next, common in nuclear physics. 'Nuclear reaction' is a specific type involving atomic nuclei.

常見錯誤

❌The chemicals reacted each other
✅The chemicals reacted with each other
💡'react' requires 'with'.

5. a way of behaving, thinking, or creating that is deliberately the opposite of a

5.名詞C1
釋義

反彈

刻意反對某事物而採取的行為或觀點

a way of behaving, thinking, or creating that is deliberately the opposite of a previous style, idea, or norm — for example, young people adopting a fashion style that rebels against older generations' tastes.

例句

The teenager's taste in music was a reaction against his parents' classical preferences.

這名青少年對音樂的喜好，是對他父母古典品味的反彈。

reaction against — followed by 'against'

Filmmaker Chidi adopted a raw, hand-held camera style as a reaction to glossy Hollywood blockbusters.

導演 Chidi 採用粗獷的手持攝影風格，作為對華麗好萊塢大片的一種反彈。

as a reaction to — prepositional phrase

同義詞
  • backlash

    stronger and more negative; implies anger or resentment from a group

  • rebellion

    more active and confrontational; 'reaction' can be quieter

反義詞
  • acceptance

    embracing rather than opposing the existing norm

文法句型

reaction + against + noun/gerund

as a reaction + to + noun

用法筆記

Frequently followed by 'against' (direct opposition) or 'to' (general response context). This sense carries a deliberate, sometimes ideological tone of rejection.

常見錯誤

❌His choice was a reaction of the current trend
✅His choice was a reaction against the current trend
💡use 'reaction against', not 'reaction of'.

6. the position that opposes reform and tries to keep society and politics from cha

6.名詞C1
釋義

反動

反對社會或政治變革的立場

the position that opposes reform and tries to keep society and politics from changing — for example, organisations that fight against new laws about equal rights or environmental standards.

例句

The election result was seen as a reaction against the government's education reforms.

這次選舉結果被視為是對政府教育改革的一種反動。

reaction against — followed by 'against' in political context

The governor's new tax on farmers triggered a reaction from growers who blocked the highway with their tractors.

州長對農民徵收的新稅引發了反動，農民們開著拖拉機堵住了公路。

triggered a reaction from + [group] who [concrete action]

同義詞
  • conservatism

    broader; includes moderate resistance to change; 'reaction' implies stronger opposition and desire to reverse

  • traditionalism

    focuses on preserving customs rather than opposing change actively

反義詞

文法句型

reaction + against + noun

forces of + reaction

用法筆記

This sense is always uncountable ('reaction', not 'a reaction' or 'reactions'). The related noun 'reactionary' describes a person who holds such beliefs. Often carries a negative connotation.

常見錯誤

❌The party represents a reaction
✅The party represents reaction' or 'The party is a reactionary force
💡this sense is uncountable.

7. [physics] a force of equal size that pushes backward when one thing pushes again

7.名詞C1
釋義

反作用力

大小相等方向相反的作用力

[physics] a force of equal size that pushes backward when one thing pushes against another — described in Newton's third law, for instance the upward push a rocket gets when it forces hot gas downward.

例句

When Felipe pushes against the wall during a standing vertical jump, the wall's reaction force propels his body upward.

Felipe 站直跳高時用手推牆，牆壁所產生的反作用力會將他的身體往上推進。

equal and opposite reaction — Newton's third law formula

A jet engine's thrust produces a reaction force that pushes the plane forward.

噴射引擎的推力會產生強大的反作用力，將飛機往前推進。

reaction force — physics collocation

文法句型

reaction + force

equal and opposite + reaction

action and + reaction

用法筆記

Often paired with 'action' as a fixed pair ('action and reaction'). In physics problems, 'reaction force' refers specifically to the force exerted by a surface against an object resting on it (normal reaction).

常見錯誤

❌The action force equals the reaction' (missing 'opposite')
✅The action force equals the reaction force and points in the opposite direction
💡Newton's third law specifies both equal magnitude and opposite direction.