一回事

• ピンイン: yī huí shì
• 漢字の分解: 一 = one; 回 = 口 within 囗 (whirlpool — a round, an occurrence, an instance); 事 = 史 (record/handle — an affair, a matter)

意味

同じこと／同一の事柄（多くは「別の話」）

Most frequently appears in contrastive structures: 是一回事 (is the same thing), 不是一回事 (is not the same thing at all), 是另一回事 (is quite another matter). A rhetorical device to draw sharp distinctions between things that might appear similar. Very common in spoken and formal written Chinese. Informal to neutral in register.

例文

1. 知道该怎么做是一回事，真正动手去做又是另一回事，中间的差距往往需要持续行动才能填补。
2. 销售额提高是一回事，利润率是否同步提升则完全是另一回事，两者不可混淆。
3. 他说支持改革是一回事，但他在董事会上的实际投票行为则是完全不同的一回事。

使い方ガイド

場面: argument, clarification, daily life, rhetoric

トーン: neutral

正しい言い方

• 法律上是否侵权是一回事，商业道德上是否妥当是另一回事，二者不能混为一谈。(Whether something is infringement in law is one matter, and whether it is proper in business ethics is another, and the two cannot be confused.)
• 懂语法是一回事，能在自然环境里流利运用是另一回事，必须靠大量输入和练习。(Knowing grammar is one matter, and being able to use it fluently in a natural setting is another; it requires plenty of input and practice.)

避ける言い方

• 我要一回事苹果 — 一回事 is a noun/predicate phrase, not a measure word; use 一个 for countable nouns; 一回事 cannot replace quantity expressions

起源と歴史

一 (one/a single) + 回 (time/occasion — 口 within 囗, originally depicting a whirlpool; extended to a round or occurrence) + 事 (matter/affair — 史 history/record; a matter that is handled)

文化的背景

時代: Modern

世代: All ages

社会的背景: Universal