同 / 与 / 而: written “with” and “and”
【六15】【六20】介词、连词 / prepositions
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
同 and 与 are the written forms of 跟 and 和. As prepositions they mean “with” or “as”: 同客户商量 (discuss it with the client), 与朋友合作, 同去年一样 (the same as last year), 与去年相比 (compared with last year). As conjunctions they mean “and” between two nouns or pronouns: 价格与质量, 我同他都是新员工.
而 does the same job for adjectives and verb phrases, never for nouns. It joins two qualities that add up (长期而稳定, 公平而合理) or that clash (贵而不好). In the second case it replaces 但是 / 可是 in a more polished way.
Formal register: contracts, articles, speeches, letters. In speech you keep 和 / 跟 for nouns and 又……又…… or 而且 for qualities. For other written links, see 以及 / 并且 (hsk4-g13).
Examples
我同他们谈过两次。
Wǒ tóng tāmen tán guo liǎng cì.I have talked with them twice.
我们要与客户保持联系。
Wǒmen yào yǔ kèhù bǎochí liánxì.We need to stay in touch with our customers.
价格与质量同样重要。
Jiàgé yǔ zhìliàng tóngyàng zhòngyào.Price and quality are equally important.
今年的产量同去年一样。
Jīnnián de chǎnliàng tóng qùnián yíyàng.This year's output is the same as last year's.
这是一个简单而有效的办法。
Zhè shì yí ge jiǎndān ér yǒuxiào de bànfǎ.This is a simple and effective method.
这家店的东西贵而不好，我不会再去了。
Zhè jiā diàn de dōngxi guì ér bù hǎo, wǒ bú huì zài qù le.The goods in this shop are expensive but not good, so I won't go back.
Common mistakes
✗ 苹果而香蕉 → ✓ 苹果与香蕉 (而 never joins nouns).
✗ 她善良与乐观 → ✓ 她善良而乐观 (to join two qualities you take 而; 与 is kept for nouns and pronouns).