昔日

• ピンイン: xī rì
• 漢字の分解: 昔 = 艹 + 日 (abbreviated flood/many + sun — originally depicted floods of the past, meaning former times); 日 = sun, day

意味

昔日；かつて

Used in formal writing, literary prose, and historical discourse to evoke a previous era or former state. Slightly more literary than 过去 or 以前. Often used in comparative contexts: 昔日的X如今已Y (the X of former days has now become Y).

例文

1. 这座昔日繁华的工业城市，如今正经历着艰难的转型与重生。
2. 昔日的同窗好友，各奔前程数十年后在同学会上重逢，感慨万千。
3. 昔日的荒野如今已成为绿意盎然的国家公园，吸引着来自各地的游客。

使い方ガイド

場面: literature, history, journalism, nostalgia, comparative description

トーン: nostalgic

正しい言い方

• 昔日黄土高原沟壑纵横、植被稀疏，如今在退耕还林推动下，绿色覆盖率明显提高，农民收入也改善了。(In the past, the Loess Plateau had gullies everywhere and sparse vegetation; now, driven by the return-farmland-to-forest policy, green coverage has risen noticeably and farmers' incomes have improved.)
• 研究近代上海变迁的历史学家说，昔日外滩的殖民金融建筑群，如今成了展示城市历史深度和文化自信的重要地标。(Historians studying modern Shanghai say that the colonial financial buildings on the former Bund have now become important landmarks showing the city's historical depth and cultural confidence.)

避ける言い方

• 昔日 in casual everyday speech for 'before' or 'in the past' — use 以前 or 过去; 昔日 is a literary or formal term with a nostalgic or historical resonance and sounds unnatural in colloquial contexts

起源と歴史

昔 (former times, the past — an ancient character depicting the sun over a flood, suggesting long-ago events) + 日 (day, days) — former days; days of old

文化的背景

世代: All ages

社会的背景: Universal