1
by itself
表示“独自地，自动地”
The door opened by itself.
门自己开了。
它自己；它本身
先理解核心含义，再看它在真实句子里的用法。
它自己；它本身
itself
The door opened by itself.
门自己开了。
它本身
pron. The neuter reciprocal pronoun of It; as, the thing is；good in itself; it stands by itself.
The heating system turns itself off at night to save energy.
供暖系统在夜间自动关闭以节省能源。
She was surprised when the door opened by itself.
门自己打开了，她感到很惊讶。
The idea itself is good, but the plan needs more work.
这个想法本身很好，但计划还需要完善。
表示“独自地，自动地”
The door opened by itself.
门自己开了。
表示“本质上，本身”，常用于评价。
The plan is fine in itself, but it needs more resources.
这个计划本身没有问题，但还需要更多资源。
Not this
The dogs hurt itself.
Use this
The dogs hurt themselves.
复数主语应用反身代词'themselves'，而非'itself'，因为'itself'只能指代单数中性名词。
Not this
The cat licked itself tail.
Use this
The cat licked its tail.
反身代词'itself'不能用作定语，表示所有格需用'its'。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
独自，单独
The machine can run by itself.
这台机器可以自己运行。
本身，本质上
The idea is not new in itself.
这个想法本身并不新颖。
不言自明
The evidence speaks for itself.
证据不言自明。
本身是目的
Education should be an end in itself.
教育本身应该是目的。
适用于，适合于
This story lends itself to adaptation.
这个故事适合改编。
表达自己
Her talent expresses itself in her art.
她的才华在她的艺术中表达出来。
独自地；自动地
The machine will start by itself when the temperature drops.
当温度下降时，机器会自动启动。
本质上；本身
The problem is not serious in itself, but it could lead to bigger issues.
这个问题本身并不严重，但可能会导致更大的问题。
本身即为目的
For many artists, creating art is an end in itself, not a means to earn money.
对许多艺术家来说，创作艺术本身就是一个目的，而不是赚钱的手段。
历史重复两次，第一次是悲剧，第二次是闹剧。
The character muttered to himself, 'History repeats itself, first as tragedy, second as farce.'
角色喃喃自语：“历史重复两次，第一次是悲剧，第二次是闹剧。”
Use itself naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
it（它）+ self（自己）→ 它本身。想象物体自指。
反身代词，中性语域，多用于书面语和正式口语，强调主语自身。
反身代词，用于强调或表示动作返回自身。
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY.