- 日复一日 rìfùyīrì day after dayday after day; day in and day out; describes the continuous passing of time
- 有朝一日 yǒuzhāoyīrì one dayone day in the future; should the day come when some event occurs
- 一日三餐 yīrìsāncān three meals a daythree daily meals; to have three meals a day
- 一日千里 yīrìqiānlǐ with giant strideslit. one day, a thousand miles; used to describe making rapid progress or a business developing very quickly
- 一日之计在于晨 yīrìzhījìzàiyúchén the morning is the best time of dayA day's plan should be made in the morning; early morning is the most precious time of the day to get things done.
- 日甚一日 rìshènyīrì getting worse by the daywith increasing intensity; becoming more serious or severe day by day
- 一日夫妻百日恩 yīrìfūqībǎirì'ēn once husband and wife, always in loveOnce a couple has been husband and wife for even a single day, they will have deep and lasting affection for each other forever.
- 一日三秋 yīrìsānqiū one day feels like three yearsA single day spent apart from a loved one feels like a long time (originally from the Classic of Poetry [[诗经|詩經|shi1 jing1]]); describes missing someone intensely
- 非一日之功 fēiyīrìzhīgōng not the work of a single daywill take much time and effort to accomplish; not something that can be achieved overnight
- 一日不如一日 yīrìbùrúyīrì to worsen day by dayTo be getting worse by the day; to decline steadily with each day.
- 一日不见，如隔三秋 yīrìbùjiànrúgésānqiū one day apart seems like three yearsOne day without seeing each other feels like three years have passed; used to describe missing someone very much.
- 一日为师，终身为父 yīrìwéishīzhōngshēnwéifù teacher for one day, father for life(idiom) even a teacher for a single day should be respected and honored like a father for the rest of one's life; expresses the deep lifelong gratitude and respect a student owes to their teacher
- 一日之长 yīrìzhīcháng slight superiorityA slight advantage or being slightly better in talent or ability than someone else
- 一日之雅 yīrìzhīyǎ casual acquaintance(idiom) a friendship of only one day; used to describe a casual acquaintance or a brief encounter between people
- 一日九迁 yīrìjiǔqiān quick promotion(idiom) to receive multiple promotions in a single day; used to describe a very rapid rise in official rank
- 冰冻三尺，非一日之寒 bīngdòngsānchǐfēiyīrìzhīhán Rome was not built in a dayLiteral meaning: ice three feet thick is not formed by one day of cold; used to express that a current situation (often a problematic one) is the result of long-term accumulation and will not be easily resolved.
- 过一日是一日 guòyīrìshìyīrì living day to daytaking things one day at a time; to live or work aimlessly without any long-term plan or ambition
