but

Compared meaning: only, merely, nothing more than this (adverb).

比较义项：仅仅，只是（副词）。

• but 本词

  In this sense but is formal and literary, meaning 'only' or 'merely'; it appears mostly in fixed phrases and old-fashioned writing, rarely in everyday speech.

  在这个意义上，but 十分正式、书面化，相当于“仅仅”“只是”，多见于固定搭配和老式书面语中，日常口语里很少这样用。

  He is but a child, and cannot be blamed for this.

  他不过是个孩子，不能因此责怪他。

• just

  Just is the most common, neutral, everyday way to say 'only'; it is casual and fits ordinary conversation and writing of any register.

  just 是表达“仅仅”最常见、最中性的说法，语气随意，适用于任何场合的日常口语和书面语。

  I just need five more minutes to finish this email.

  我只需要再花五分钟就能写完这封邮件。

• simply

  Simply adds emphasis, presenting the limitation in a plain, direct way, and can even shade into 'completely'; here it stresses how plainly true the fact is.

  simply 带有强调意味，把这种“仅仅”表达得更加干脆、直接，有时还可以带有“完全”的语气；这里强调事实的单纯明显。

  She simply refuses to apologize, no matter what anyone says.

  不管别人说什么，她就是不肯道歉。

• only

  Only is the most basic, general, and frequent word for this meaning, used freely in both speech and writing, with flexible position in the sentence.

  only 是表达这个意义最基本、最通用、最常见的词，口语和书面语中都自由使用，在句中的位置也很灵活。

  I only wanted a small slice of cake, not the whole thing.

  我只是想要一小块蛋糕，不是整个蛋糕。

But, just, only, and simply can all mean 'only', but usage differs. But is formal and literary here, rare in speech. Just and only are the most common, natural in speech and writing. Simply is stronger and more direct. But's meaning 'however' is not compared.

这几个词在“仅仅、只是”这一意义上相近，但语气和使用场合不同：but 在此义项下非常正式、书面化，现代口语中很少见；just 和 only 最常用、最口语化，可自由用于书面语和口语；simply 语气更强调、更加直接。这里不比较 but 用作转折连词（意为“但是”）的用法。