1
it is unnecessary to do sth
常用于引导不定式短语。
It is unnecessary to worry about the outcome.
没有必要担心结果。
不必要的；不需要的
先理解核心含义，再看它在真实句子里的用法。
不必要的；不需要的
Not needed; not necessary.
It is unnecessary to worry about the outcome.
没有必要担心结果。
Not needed or necessary.
不必要的
not necessary
Done in addition to requirements; unrequired.
We should avoid unnecessary risks when driving at night.
我们夜间开车时应避免不必要的风险。
The report was full of unnecessary details that made it hard to read.
这份报告充斥着使阅读困难的多余的细节。
Please don't make any unnecessary noise in the library.
请不要在图书馆里制造任何不必要的噪音。
常用于引导不定式短语。
It is unnecessary to worry about the outcome.
没有必要担心结果。
表示对某人或某物而言不必要。
This warning is unnecessary for experienced users.
这个警告对有经验的用户来说没有必要。
直接修饰名词，表示多余的。
Unnecessary expenses should be avoided.
应避免不必要的开支。
Not this
He unnecessary left early.
Use this
He unnecessarily left early.
形容词 'unnecessary' 不能修饰动词；应使用其副词形式 'unnecessarily' 作状语。
Not this
It is an unnecessary.
Use this
It is unnecessary.
'unnecessary' 是形容词，不能直接作名词；应省略冠词，或改为 'an unnecessary thing'。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
不必要的开支
We should avoid any unnecessary expense during the project.
在项目期间，我们应该避免任何不必要的开支。
不必要的风险
Don't take unnecessary risks when driving in bad weather.
在恶劣天气驾驶时不要冒不必要的风险。
不必要的麻烦
She went to great lengths to save him unnecessary trouble.
她尽力避免给他带来不必要的麻烦。
不必要的延误
Please proceed without unnecessary delay.
请立即进行，不要有不必要的延误。
不必要的复杂化
We should simplify the process and avoid any unnecessary complication.
我们应该简化流程，避免任何不必要的复杂化。
不必要的负担
The new regulations place an unnecessary burden on small businesses.
新规定给小企业带来了不必要的负担。
Use unnecessary naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
前缀un-像'不'，所以unnecessary = '不必要'，记住这个前缀就能记住。
通常用于正式或中性语境，如学术写作、商务沟通和日常对话，不带有强烈的褒贬色彩。
常与不定式连用，表示‘做某事是不必要的’。
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY.