observe

Compared meaning: to become aware of something (verb).

比较义项：留意到、察觉到某事物（动词）。

• observe 本词

  Implies careful, deliberate, and often sustained watching, typically in a formal or scientific context; not used for a brief, accidental perception.

  强调有意、仔细且往往持续的观察，常用于正式或科研语境；不用于表示偶然、短暂的察觉。

  Researchers observe the chimps for hours to understand their social behavior.

  研究人员连续数小时观察黑猩猩，以了解它们的社会行为。

• detect

  Implies discovering something hidden, faint, or hard to perceive, often with instruments or keen senses; not used for openly watching an obvious activity over time.

  强调发现隐藏、微弱或不易察觉的事物，常借助仪器或敏锐的感官；不用于表示长时间公开观察明显的活动。

  The smoke detector can detect a fire within seconds of it starting.

  烟雾报警器能在起火后几秒内探测到火情。

• notice

  The plain, everyday word for becoming aware of something, often without deliberate effort or over a short moment; more general and informal than the other two.

  是最普通、日常的说法，表示无意中或短时间内察觉到某事物，比另外两个词更笼统、更口语化。

  I didn't notice the new sign until my friend pointed it out.

  在朋友指出之前，我一直没注意到那块新标牌。

All three mean noticing something. Observe means watching carefully, often in formal settings. Detect means finding something hidden or faint, using instruments. Notice is the plain, everyday word for becoming aware without effort. The noun notice and 'observe a rule' are not compared here.

这三个词在“注意到、察觉到某事物”这一意义上相近，但语气和用法不同：observe强调有意、持续地仔细观察，常用于科研或正式语境；detect强调发现隐藏、微弱或不易察觉的事物，常借助仪器或敏锐的感官；notice是最普通、口语化的说法，表示无意中或短时间内察觉到某事。这里不比较notice作名词表示“通知”的用法，也不比较observe表示“遵守（规则、法律）”的用法。

Compared meaning: to mention something and comment on it (verb).

比较义项：提及或谈到某事，并就此作出简短评论（动词）。

• observe 本词

  Formal: introduces the speaker's own comment or judgment, as if reached by careful watching or thinking, common in writing or careful speech.

  正式用语：像是经过观察或思考后提出自己的看法或评论，常用于书面语或谨慎的口语表达。

  The critic observed that the film's pacing was uneven in the second half.

  这位影评人评论说，这部电影下半部分的节奏不稳。

• note

  Neutral-to-formal: points out a specific fact worth paying attention to, common in reports, documents, or official statements.

  中性偏正式：指出一个应引起注意的具体事实，常见于报告、文件或正式陈述中。

  The report noted that sales had dropped sharply in the last quarter.

  报告指出，上一季度销售额大幅下降。

• mention

  Casual and brief: refers to something in passing without emphasis or detail, common in everyday conversation.

  随意且简短：顺带提及某事，不作强调或展开，常见于日常对话。

  She mentioned that she might be moving to Boston next year.

  她提到她明年可能会搬到波士顿。

All three mean mentioning something with a comment. Observe is formal, giving the speaker's own careful opinion. Note points out a fact worth attention, common in reports. Mention is casual, referring to something briefly. Observe (watch) and note (a short message) are not compared here.

这三个词在“提到、评论某事”这个意义上很接近，但语气和使用场合不同：observe 较为正式，像是经过观察或思考后提出自己的看法；note 强调指出一件值得注意的事实，常见于报告或书面语；mention 最随意，只是顺带提一下，不作强调。这里不比较 observe 的“观察，观测”义，也不比较 note 的“记录，便条”义。