Number/Demonstrative + 桩 + Noun (affair/matter)
The classifier 桩 (zhuāng) is used to count affairs, matters, or events, particularly those that are significant or noteworthy. It is a formal measure word often seen in legal, literary, or narrative contexts. Use 桩 with demonstratives or numbers before nouns like 事, 案, or 婚事.
这是一桩大事,不能马虎。
zhè shì yì zhuāng dàshì, bù néng mǎhu.
This is a big matter — it can't be handled carelessly.
警方正在调查那桩案件。
jǐngfāng zhèngzài diàochá nà zhuāng ànjiàn.
The police are investigating that case.
他们的婚事是一桩美事。
tāmen de hūnshì shì yì zhuāng měishì.
Their marriage is a wonderful match.