Word · CEFR A2 · Frequency #555
necessary
必要的；必需的
核心释义
Required, essential; needed to achieve a result or avoid a penalty.
- 1.
必需的,不可或缺的
Required, essential, whether logically inescapable or needed in order to achieve a desired result or avoid some penalty.
- 2.
不可避免的,必然的
Unavoidable, inevitable.
- 3.
绝对必要的
absolutely essential
- 4.
由先前情况不可避免地决定的
unavoidably determined by prior circumstances
不可避免的；必然的；必需的,不可或缺的；不可避免的,必然的；绝对必要的；由先前情况不可避免地决定的
用法In use
It is necessary to bring a valid ID to the exam.
用法提示：necessary 作表语，后接不定式，表示必要性。
Water is necessary for all living things.
用法提示：necessary 作表语，后接介词 for，表示对……是必需的。
She made the necessary arrangements for the trip.
用法提示：necessary 作定语，修饰名词 arrangements。
the necessary consequences of one's actions
it is necessary (for sb) to do sth
It is necessary for you to finish the report today.
你今天必须完成报告。
be necessary for sth
相关词与表达Connections
搭配Collocations
- necessary evil
- 不得不接受的坏事；必要之恶
- Paying taxes is a necessary evil.纳税是一件不得不接受的坏事。
- necessary condition
- 必要条件
- A valid passport is a necessary condition for international travel.有效护照是国际旅行的必要条件。
- necessary measures
- 必要措施
- The government took necessary measures to prevent the spread of the disease.政府采取了必要措施防止疾病传播。
- if necessary
- 如有必要；如果需要的话
- You can call me if necessary.如有必要，你可以给我打电话。
- necessary skills
学习提示Learner notes
记忆技巧Memory Tip
记忆联想：necessary 拼写里有“两个 s”，像两件必需的物品；缺一个 s，就不再必要了。
语境与语域Context & Register
语域：neutral 常见场景：日常交流、正式写作、逻辑论述 necessary 在口语和书面语中都较常用，表示“必需的；必然的”时属于中性用词；在正式学术、法律等文本中也很常见，通常可用 it is necessary to 等结构。
发音与拼写Pronunciation & Spelling
No common word exactly rhymes with necessary /ˈnɛsəsrɪ/. Adversary and accessory are spelling lookalikes (-sary/-ssory) but differ in stress and vowels. Sensory and nursery share a similar final /səri/ sound; salary and temporary are common -ary words. None is an exact rhyme.
高价值词汇High-value vocabulary
该词属于 Oxford 核心词汇，值得优先掌握常见搭配和句型。
用法优先级Usage priority
Collins 词频等级为 4，建议结合例句记忆，而不是只背中文释义。
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WORDNET.