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JLPT N4Time Expressions

〜おきに— The Gap Logic (Intervals)

Expresses regular intervals between repeated occurrences — "every [other] [unit]" or "at every [distance]." It focuses on the empty gap between occurrences.

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Pro lessonUNIT 49 · TIME EXPRESSIONS

Structure · 形

[Number + Unit] + おきに

Examples · 例文

  • 3時間おきに薬を飲んでください。

    Sanjikan oki ni kusuri wo nonde kudasai.

    Please take medicine every 3 hours (with 3-hour gaps).

    3時間 (interval) + おきに

  • 電柱は50メートルおきに立っています。

    Denchuu wa gojuu meetoru oki ni tatte imasu.

    Utility poles stand every 50 meters.

    50m (physical interval) + おきに

  • 一日おきに宿題が出る。

    Ichinichi oki ni shukudai ga deru.

    Homework is assigned every other day.

    一日おきに = a one-day gap (Mon, Wed, Fri...)

Usage notes · 注意

  • Gap vs Count: 3時間おきに means there is a 3-hour GAP between events. 3時間ごとに means 'at each 3-hour mark'.
  • Common Trap: 一日おき is 'every other day' because the gap is one full day. 二日おき is 'every third day'.
  • Note: Used for both time and physical distance (meters, steps).

Commonly confused with

The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones 〜おきに is tested against.

vsごとに

ごとに means 'at each' point (every 3rd hour hits the mark); おきに emphasizes the GAP between, so 一日おき = every OTHER day.

vs毎〜 (毎日/毎週)

毎 means 'every single' unit without gaps (毎日 = every day); おきに inserts a skipped interval between occurrences.

More time expressions

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