# 一边……一边…… vs 又……又…… vs 既……又……: "Both" and "At the Same Time"

Source: https://sentencecoach.com/grammar/ji-you-yibian
Level: HSK 2–4

Use 一边 + Verb 1 + 一边 + Verb 2 when one person does two physical actions at the same time ("while doing A, doing B"): 他一边听音乐一边做饭. Use 又 + Adj 1 + 又 + Adj 2 (or 既 + A + 又/也 + B) to combine two qualities, states or mental verbs that hold true together ("both A and B"): 这个西瓜又大又甜, 她既聪明又努力. Never use 一边……一边…… with adjectives.

Patterns:
- Subject + 一边 + Verb 1，一边 + Verb 2: Two simultaneous actions: 一边走一边聊.
- Subject + 又 + Adj 1 + 又 + Adj 2: Two qualities in the same direction (short adjectives).
- Subject + 既 + Adj/Verb 1，又 / 也 + Adj/Verb 2: More formal "both … and …"; works with 1- or 2-syllable words and verbs.

Examples:
- 他喜欢一边喝咖啡，一边看报纸。 (tā xǐ huan yì biān hē kā fēi, yì biān kàn bào zhǐ.) — He likes drinking coffee while reading the newspaper.
- 这家超市的水果又新鲜又便宜。 (zhè jiā chāo shì de shuǐ guǒ yòu xīn xiān yòu pián yi.) — The fruit at this supermarket is both fresh and cheap.
- 这样做既能节省时间，又能少花钱。 (zhè yàng zuò jì néng jié shěng shí jiān, yòu néng shǎo huā qián.) — Doing it this way both saves time and costs less money.

Common mistakes:
- ✗ 这件衣服一边好看一边便宜。 → ✓ 这件衣服又好看又便宜。 / 这件衣服既好看又便宜。: Adjectives and states take 又……又…… or 既……又……; 一边……一边…… is only for two active verbs.
- ✗ 这家店的东西又便宜又贵。 → ✓ 这家店有的东西便宜，有的东西贵。: 又 A 又 B must combine two compatible qualities (both positive or both negative), never opposites.

FAQ:
- Q: Can 一边 be shortened to 边?
  A: Yes, with single-character verbs: 边走边聊 (walk and chat) and 边吃边看 (eat and watch) are very natural.