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reason for + noun/gerund
for后接名词或动名词，表示某事的原因
What is the reason for the delay?
延迟的原因是什么？
原因；起因
reasons — plural of reason
先理解核心含义，再看它在真实句子里的用法。
原因；起因
A cause of an event or situation.
What is the reason for the delay?
延迟的原因是什么？
原因
A cause:
墙顶板
A wall plate.
信念或行动的理性动机
a rational motive for a belief or action
理性思维(或思维能力)；概念、判断、推理和直觉等认知能力的总和。
Rational thinking (or the capacity for it); the cognitive faculties, collectively, of conception, judgment, deduction and intuition.
What is the reason for your decision?
你做出这个决定的理由是什么？
AI contextual example
There are several reasons why we should leave early.
有几个理由说明我们应该早点离开。
AI contextual example
Use your reason to solve the problem.
运用你的理性来解决问题。
AI contextual example
the reason that war was declared
宣战的原因。
WordNet
for后接名词或动名词，表示某事的原因
What is the reason for the delay?
延迟的原因是什么？
表示做某事的理由，常用于否定或疑问句
There is no reason to worry.
没有理由担心。
why引导定语从句，口语中常省略why
The reason why she left is still unknown.
她离开的原因仍然未知。
Not this
The reason of the problem is unclear.
Use this
The reason for the problem is unclear.
reason 表示“理由”或“原因”时，后面应接介词 for，而不是 of。中文常说的“…的原因”会导致误用 of，但英语习惯用 reason for。
Not this
The reason is because he was late.
Use this
The reason is that he was late.
reason 后面不能接 because 引导的从句，因为 because 本身就是表原因，造成语义重复。应使用 that 引导同位语从句来说明理由内容。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
主要原因
The main reason for the delay was the weather.
延误的主要原因是天气。
…的原因
There is no reason for concern.
没有担心的理由。
…的原因
I don't know the reason why he left.
我不知道他离开的原因。
由于，因为
He was excused by reason of his age.
他因为年龄原因被免除了。
合乎道理
It stands to reason that you will improve with practice.
合乎道理的是，你会通过练习提高。
有理由地
She complained with reason.
她有理由地抱怨。
合乎道理
It stands to reason that if you work harder, you will achieve better results.
如果你更努力，就会取得更好的成绩，这是合乎道理的。
在合理范围内
You can buy whatever you want, within reason.
在合理范围内，你可以买任何你想要的东西。
由于
He was excused by reason of his age.
他由于年龄的原因被原谅了。
心有它自己的道理，这是理性所不知道的。
The heart has its reasons that reason doesn't know.
心有它自己的道理，这是理性所不知道的。
发长 /iː/ 音 (如 sea, tea)
Same pattern, same sound
Use reasons naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
拆解为re（重复）和son（儿子），重复给儿子讲道理，即理由与理性。
语域：neutral 常见场景：argumentation、explanation、reasoning reason作为名词表示理由或原因时，注册为中性的，广泛适用于日常对话、书面论述和学术语境。
表示'理性'时不可数，表示'原因'时可数
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY, WORDNET.
Watch the sound change