In short

To stack two qualities that are both true at once, wrap them in 又……又…… (yòu … yòu …, both … and …): 又便宜又好吃 (yòu piányi yòu hǎochī, both cheap and tasty). To add a stronger, further point - “not only … but also” - use the matched pair 不但……而且…… (búdàn … érqiě …). Both are two-part frames, so the trap is the same as with all Chinese complex sentences: keep the second word.

The rule

Chinese has no single word “and” for joining two clauses. Instead it uses matched pairs, and they split into two jobs. Coordinate connectors (并列, bìngliè) stack two facts as equals - “both A and B.” Additive / progressive connectors (递进, dìjìn) add a second point that outranks the first - “not only A, but even B.” Learn each as a two-part unit.

Step 1 - Parallel qualities: 又……又……. This is the everyday “both … and …,” linking two adjectives or two verb phrases that are simultaneously true of the same subject.

Subject + 又 + A + 又 + B

他又高又帅。 (Tā yòu gāo yòu shuài, he’s both tall and handsome.) Two things to notice. First, the adjectives stand bare - the 很 (hěn) that a lone adjective normally needs (see Adjectival predicate and degree adverbs) is dropped inside the frame. Second, this 又 is not “again” - the doubled frame is what gives the “both” meaning; the standalone 又 (“once more,” lesson 23) is a different word.

Step 2 - The formal twin: 既……又……. 既 (jì) opens a parallel pair in the same “both … and …” sense, but is more written / bookish; the second half takes 又 or 也 (yě). 这个办法既简单又有效。 (Zhège bànfǎ jì jiǎndān yòu yǒuxiào, this method is both simple and effective.) Use 又……又 when you speak, 既……又 when you write.

Step 3 - Two aspects: 一方面……（另）一方面……. 一方面 (yì fāngmiàn, on one hand) presents two co-existing sides of a situation; the second is often marked 另一方面 (lìng yì fāngmiàn, on the other hand). 这份工作一方面能赚钱，另一方面能学到东西。 (Zhè fèn gōngzuò yì fāngmiàn néng zhuànqián, lìng yì fāngmiàn néng xué dào dōngxi, this job earns money on one hand and lets you learn things on the other.)

Step 4 - Progressive addition: 不但……而且……. This is “not only A, but also B,” where B is a further or stronger point. 不但 (búdàn) opens clause 1, 而且 (érqiě) opens clause 2.

不但 + A，而且 + B

Placement depends on the subject. If one subject runs through both clauses, it comes first and 不但 follows it: 他不但会说英语，而且会说法语。 (Tā búdàn huì shuō Yīngyǔ, érqiě huì shuō Fǎyǔ, he can speak not only English but also French.) If the two clauses have different subjects, 不但 leads the whole sentence: 不但老师满意，而且家长也满意。 (Búdàn lǎoshī mǎnyì, érqiě jiāzhǎng yě mǎnyì, not only is the teacher satisfied, the parents are too.) The second half also accepts 还 (hái) or 也 (yě) instead of 而且, and 不但 has a more formal cousin 不仅 (bùjǐn).

Step 5 - Adding a further action: 并且. 并且 (bìngqiě, and moreover / furthermore) joins two predicates or clauses of the same subject, tacking on an additional action or point. 我们讨论了这个问题，并且做出了决定。 (Wǒmen tǎolùn le zhège wèntí, bìngqiě zuòchū le juédìng, we discussed the problem and moreover reached a decision.)

Forms & patterns

The coordinate and additive connectors at a glance:

Where 不但 sits depends on the subjects:

Examples

Common mistakes

• 他又很高又很帅。 -> 他又高又帅。 - Inside the 又……又 frame the adjectives stand bare; the 很 a lone adjective needs is dropped.
• 他会说英语和会说法语。 -> 他不但会说英语，而且会说法语。 - 和 joins nouns, not verb phrases or clauses; to add a second predicate use 又……又 or 不但……而且.
• 他不但聪明，但是很努力。 -> 他不但聪明，而且很努力。 - 不但 pairs with 而且／还／也 (addition), never with 但是 (contrast) - 但是 would reverse the meaning.
• 这个方法既简单而且有效。 -> 这个方法既简单又有效。 - 既 pairs with 又 (or 也), never with 而且.
• 不但他会说英语，而且他会说法语。 -> 他不但会说英语，而且会说法语。 - When both clauses share one subject, the subject comes first and 不但 follows it; 不但 leads only when the two clauses have different subjects.

Tips

• 又……又 describes; 不但……而且 argues. Use 又……又 to pile up two co-existing traits on equal footing (“both A and B”). Use 不但……而且 to escalate - B is a further, often stronger point (“not only A, but even B”). Pick the frame by what you’re doing: painting a picture, or building a case.
• This 又 is not “again.” Only the doubled 又……又 means “both … and …”; the standalone 又 (“once more,” lesson 23) is a separate word. Never read one 又 in the pair as repetition.
• Register ladder. 又……又 is everyday speech; 既……又 is its formal twin (writing, set phrases). Likewise 不但 has the bookish variant 不仅 (bùjǐn) - same pattern, higher register.
• Tone watch. 不但 is búdàn (不 shifts bù -> bú before the 4th-tone 但), and 一方面 is yì fāngmiàn (一 shifts yī -> yì before the 1st-tone 方). Say the sandhi, not the citation tone.