你一句我一句 / 东一句西一句: back and forth, here and there
【六35】【六36】固定格式 / set structures
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
A + 一 + measure word，B + 一 + measure word sets two sides face to face with the same measure word: 你一句，我一句 ("you one line, me one line": everyone chips in, in turn), 你一杯，我一杯 (glass after glass), 青一块，紫一块 (black and blue patches all over). A and B are people, camps or colours; the effect is a lively scene with many voices.
东 + 一 + measure word，西 + 一 + measure word means "a bit here, a bit there": acts or objects are scattered, with no order or follow-through. 东一句，西一句 (talk in a rambling way), 东一下，西一下 (work in fits and starts), 东一件，西一件 (clothes thrown here and there). 东 (east) and 西 (west) no longer mean compass points: they stand for "here" and "there". It is most often a reproach or an unflattering remark.
In both patterns the measure word is the same in both halves and the number is always 一. Register: spoken, vivid, with a four-plus-four rhythm. Don't mix them up with 一问一答 (hsk6-g32), where 一 links two different words; here the same measure word comes back.
Examples
同学们你一句我一句，聊得停不下来。
Tóngxuémen nǐ yí jù wǒ yí jù, liáo de tíng bu xiàlái.The classmates chip in one after another and can't stop chatting.
两个人你一杯我一杯，不知不觉都喝多了。
Liǎng ge rén nǐ yì bēi wǒ yì bēi, bù zhī bù jué dōu hē duō le.Trading glass for glass, the two of them drank too much without noticing.
他摔得不轻，身上青一块，紫一块。
Tā shuāi de bù qīng, shēn shang qīng yí kuài, zǐ yí kuài.He took a bad fall: he's black and blue all over.
他说话东一句，西一句，听了半天也不知道他想说什么。
Tā shuōhuà dōng yí jù, xī yí jù, tīng le bàntiān yě bù zhīdào tā xiǎng shuō shénme.He rambles from one thing to another: after ages I still don't know what he wants to say.
他的衣服东一件，西一件，扔得满屋子都是。
Tā de yīfu dōng yí jiàn, xī yí jiàn, rēng de mǎn wūzi dōu shì.His clothes are scattered here and there, thrown all over the room.
Common mistakes
✗ 东一句，西一个 → ✓ 东一句，西一句 (both halves take 一 + the same measure word).
✗ 身上青一个，紫一个 → ✓ 身上青一块，紫一块 (pick the measure word that fits a patch: 块).
✗ 一句你，一句我 → ✓ 你一句，我一句 (the person or side first, then 一 + measure word).