不但 (búdàn) vs 不光 (bùguāng): formal vs colloquial 'not only'
Both 不但 and 不光 mean 'not only' and generally pair with 而且 (érqiě) or 还 (hái) to form 'not only… but also…' constructions. The core difference is register: 不光 is the colloquial, everyday counterpart, while 不但 is more formal and common in written Chinese. Choosing the right one depends on the tone of the context.
不但 and 不光 both introduce 'not only' clauses and are typically followed by 而且 (érqiě) or 还 (hái) to express 'not only… but also…'. The primary distinction is register: 不但 is neutral-to-formal and widely used in both speech and writing, while 不光 is distinctly colloquial and should be avoided in formal or academic prose. In everyday conversation, 不光 often sounds more natural than 不但, but 不但 is never incorrect in casual speech. Both can be negated (e.g., 不但是, 不光不是, though 不光不是 is rare). Context and audience determine which is appropriate.
When to use each
Use 不但 in formal or neutral contexts: academic papers, news reports, speeches, professional writing, or when you want to sound slightly elevated. It is also perfectly acceptable in spoken Chinese, though it may feel a bit stiff in very casual chats.
不但 can sometimes be used without a following 而且/还, especially in written parallel structures, but this is less common.
Use 不光 in informal conversation, personal messages, casual writing, or when mimicking spoken language. It is the go-to choice for everyday 'not only' statements among friends, family, or in relaxed settings.
不光 also means 'not bright' (e.g., 天不光, 'the sky is not light'), but the context clearly separates the two meanings.
At a glance
| 不但 | 不光 | |
|---|---|---|
| Register | Formal / neutral | Colloquial |
| Common in writing | Yes, standard in formal texts | Rare in formal writing, common in casual |
| Common in speech | Yes, but often sounds formal | Yes, very natural and frequent |
| Typical pairing | 不但…而且… | 不光…还… |
| Negation (e.g., 'not only not') | 不但不 (búdàn bù) | 不光不 (bùguāng bù) – possible but less common |
Examples
- 不但他不但聪明，而且很努力。Tā búdàn cōngming, érqiě hěn nǔlì.He is not only smart, but also very hardworking.Formal construction suitable for writing or speech.
- 不但我不但去过北京，还去过上海。Wǒ búdàn qù guo Běijīng, hái qù guo Shànghǎi.I have not only been to Beijing, but also to Shanghai.Use of 不但 + 还, neutral tone.
- 不光我不光喜欢唱歌，还喜欢跳舞。Wǒ bùguāng xǐhuan chànggē, hái xǐhuan tiàowǔ.I not only like singing, but also like dancing.Colloquial, natural in conversation.
- 不光他不光会说英文，还会说法文。Tā bùguāng huì shuō Yīngwén, hái huì shuō Fǎwén.He not only speaks English, but also speaks French.Everyday spoken usage with 还.
Common mistakes
- Using 不光 in formal essays or business emails where 不但 is expected.
- Forgetting to include 而且/还 after 不但/不光, leaving the sentence incomplete.
- Assuming 不光 is always interchangeable with 不但 – register makes them non-interchangeable in formal writing.
- Using 不但 in very casual spoken sentences, which can sound bookish or unnatural.
- Confusing 不光 (not only) with its homophone meaning 'not bright' without contextual clues.
FAQ
- When do I use 不但 vs 不光?
- Use 不但 in formal or neutral contexts (writing, speeches, polite conversation). Use 不光 in relaxed, everyday speech. In casual chat, 不光 is more natural.
- Can 不光 be used in formal writing?
- Generally no. In academic papers, reports, or professional correspondence, stick to 不但. 不光 may appear in direct quotations of speech or in informal blogs, but avoid it in formal genres.
- Do 不但 and 不光 always need a following 而且/还?
- They typically do, especially in modern Chinese. However, in certain parallel expressions (e.g., 他不但聪明，勤奋，而且有耐心), the second 而且/还 can be omitted if the first completes the 'not only' part, but this is less common.
- Is 不光不 (bùguāng bù) correct for 'not only not'?
- Yes, it is possible but much less common than 不但不. For example: 他不光不去，还骂人 (Tā bùguāng bù qù, hái mà rén). Prefer 不但不 in most contexts.