decay

decay — 動詞

1. to become gradually weaker, more damaged, or less effective over time, or to cau

1.動詞及物 / 不及物B1
釋義

腐壞；衰敗

逐漸損壞、變弱或惡化

to become gradually weaker, more damaged, or less effective over time, or to cause this to happen. For example, a tooth decays when acid breaks down the enamel, a building decays when no one repairs it, or a relationship decays when trust erodes.

例句

The wooden fence had begun to decay after years of rain and sun.

那道木籬笆經過多年的日曬雨淋，已經開始腐壞。

intransitive: [material] + decay after + [conditions]

If you do not brush your teeth every day, they will decay and hurt.

如果你每天不刷牙，牙齒就會蛀掉並開始疼痛。

同義詞
  • rot

    more specific to organic material breaking down, often with a smell

  • deteriorate

    more formal; can apply to abilities, conditions, or situations

  • decompose

    technical term for organic matter breaking down chemically

  • decline

    focuses on losing quality or strength rather than physical damage

反義詞

文法句型

decay (intransitive): [subject] decays

decay + noun phrase (transitive): [agent] decays [object]

用法筆記

Commonly used without a direct object (intransitive). The transitive form ('Something decays something else') is rarer and typically used for teeth or organic matter.

常見錯誤

❌My shoes decayed after a year of use.
✅My shoes wore out after a year of use.
💡'Decay' is for natural rotting or chemical breakdown, not general wear and tear.
❌The milk decayed in the fridge.
✅The milk went bad in the fridge.
💡For food that becomes unsafe to eat, 'go bad' or 'spoil' are more natural than 'decay'.

2. when a radioactive substance such as uranium or carbon-14 changes naturally into

2.動詞不及物C1
釋義

衰變

放射性物質釋出輻射轉變為他物

when a radioactive substance such as uranium or carbon-14 changes naturally into another substance by releasing radiation from its atoms

例句

Uranium-238 decays into thorium-234 by releasing an alpha particle.

鈾-238 釋放出α粒子後衰變成釷-234。

[element] + decays into + [element]

Scientists measure how fast a radioactive material decays to find out how old something is.

科學家測量放射性物質的衰變速度，藉此判斷物品的年齡。

同義詞
  • break down

    less technical, describes the process in everyday language

  • disintegrate

    suggests the nucleus breaking apart into smaller pieces

文法句型

decay + into + noun phrase (resulting element)

用法筆記

Subject is always a radioactive element or isotope. The rate of decay is constant for each substance and cannot be changed by outside conditions.

常見錯誤

❌The scientist decayed the uranium in the lab.
✅The uranium decayed naturally in the lab.
💡'Decay' for radioactive substances is always intransitive; no one can 'decay' a radioactive element.

decay — 名詞