Among them / of which (其中)

Structure Mentioned set，其中 + part = "of which / among them, …"

其中 (qízhōng) means "among them / of which / within that set". It is a partitive anaphor: it presupposes an already-named group and points to a part of it. 他买了三本书，其中一本是中文的 = "he bought three books, one of which is in Chinese". It is extremely common in expository and journalistic prose for breaking out a portion of a whole. It joins 其 ("that, of them") with 中 ("within"); it cannot stand without a previously mentioned set.

Examples

他tā买mǎi了le三sān本běn书shū，其qí中zhōng一yī本běn是shì中zhōng文wén的de。
He bought three books, one of which is in Chinese.
会huì上shàng提tí出chū了le多duō项xiàng建jiàn议yì，其qí中zhōng不bù乏fá可kě行xíng之zhī策cè。
Several proposals were raised at the meeting, among them no shortage of workable measures.
公gōng司sī裁cái员yuán两liǎng百bǎi人rén，其qí中zhōng多duō数shù是shì临lín时shí工gōng。
The company laid off two hundred people, most of them temporary workers.

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.

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