（在）……下

(zài) … xià

Meaning

（在）……下 is a pattern meaning “under…”, “with…”, “in the situation of…”. It marks the condition, influence or help under which something happens. 在 is usually there, but it can be dropped.

Basic structure

（在）+ Modifier + Disyllabic noun / verb + 下，…

Examples

一(Yī)般(bān)情(qíng)况(kuàng)下(xià)，你(nǐ)花(huā)的(de)钱(qián)越(yuè)多(duō)，买(mǎi)的(de)东(dōng)西(xi)也(yě)就(jiù)越(yuè)好(hǎo)。

Generally, the more money you spend, the better the things you buy.

在(Zài)冬(dōng)天(tiān)比(bǐ)较(jiào)冷(lěng)的(de)情(qíng)况(kuàng)下(xià)，吃(chī)碗(wǎn)热(rè)面(miàn)条(tiáo)会(huì)让(ràng)人(rén)觉(jué)得(de)很(hěn)舒(shū)服(fu)。

When winter is cold, a bowl of hot noodles makes you feel wonderful.

在(Zài)老(lǎo)师(shī)和(hé)同(tóng)学(xué)们(men)的(de)帮(bāng)助(zhù)下(xià)，他(tā)的(de)汉(Hàn)语(yǔ)提(tí)高(gāo)得(de)非(fēi)常(cháng)快(kuài)。

With the help of his teacher and classmates, his Chinese improved very quickly.

Common expressions

一般情况下 — under normal circumstances 在……帮助下 — with the help of… 在……影响下 — under the influence of… 在……领导下 — under the leadership of… 在……条件下 — under … conditions 在……环境下 — in … surroundings

（在）……下 vs. 在……里

在(Zài)大(dà)家(jiā)的(de)帮(bāng)助(zhù)下(xià)，他(tā)成(chéng)功(gōng)了(le)。

With everyone's help, he succeeded.

他(Tā)在(zài)房(fáng)间(jiān)里(lǐ)做(zuò)作(zuò)业(yè)。

He's doing his homework in the room.

（在）……下 → a condition, cause or influence. 在……里 → a place or a span of time.

Remember: （在）……下 = under…, with…, in the situation of… It names the condition something happens under. A very common pattern.