By the thousands (成千上万)

Structure 成千上万 / 成百上千 + (的) + noun

成千上万 (chéngqiān-shàngwàn, lit. "making thousands, rising to tens of thousands") is an emphatic quantity idiom: "by the thousands, in their thousands, a multitude". 成千上万的人涌上街头 = "people poured into the streets by the thousands". Its sibling 成百上千 (chéngbǎi-shàngqiān) is one notch lower, "by the hundreds". It gives no figure; it stresses how overwhelming the number is. It usually precedes the noun with 的 and is written or elevated journalistic register.

Examples

成chéng千qiān上shàng万wàn的de人rén涌yǒng上shàng街jiē头tóu庆qìng祝zhù。
People poured into the streets by the thousands to celebrate.
每měi年nián有yǒu成chéng千qiān上shàng万wàn的de候hòu鸟niǎo在zài此cǐ停tíng留liú。
Every year migratory birds stop here by the thousands.
这zhè场chǎng灾zāi难nàn夺duó去qù了le成chéng千qiān上shàng万wàn人rén的de生shēng命mìng。
That disaster claimed the lives of thousands upon thousands.
展zhǎn会huì上shàng摆bǎi放fàng着zhe成chéng百bǎi上shàng千qiān件jiàn展zhǎn品pǐn。
The fair displayed exhibits by the hundreds.

Levels are indicative: they follow the standard Chinese Grammar Wiki (AllSet Learning) progression, not an official HSK 3.0 mapping. We never assign levels by eye.

This point and the other 370, with audio on every example, inside Wanyu.