
Is
とうきょうと おおさかの あいだは しんかんせんが 五分ごとに はしっています。
exactly the same as
とうきょうと おおさかの あいだは しんかんせんが 五分おきに はしっています。
?
In this example, both ごふんごと and ごふんおき mean “every 5 minutes.” When the emphasis is on the continuity/repetition of events with a short interval measured by units like 秒 (seconds)、分 (minutes)、センチ (centimeters), etc., ごと and おき mean basically the same.
苗(なえ)は50センチおきに植(う)えます。Plant the seedlings 50 cms apart.
=苗(なえ)は50センチごとに植(う)えます。Plant the seedlings at every 50 cms.この薬(くすり)を八時間(はちじかん)おきに飲(の)んでください。Please take this medicine 8 hours apart.
=この薬(くすり)を八時間(はちじかん)ごとに飲(の)んでください。Please take this medicine every 8 hours.
However, as ごと means “every” and おき has the emphasize on the interval between events/items, if we are talking about clearly separated items, like lines and people as shown below, ごと and おき have clearly different meanings.
一行(いちぎょう)ごとに名前(なまえ)を書(か)いてください。
Write your name on every line.
一行(いちぎょう)おきに名前(なまえ)を書(か)いてください。
Write your name with one line apart = Write your name on every second line.一人(ひとり)ごとに名前(なまえ)を呼(よ)ばれた。(For this, 一人ずつ sounds more natural).
Every person’s name got called out.
一人(ひとり)おきに名前(なまえ)を呼(よ)ばれた。
Every second person’s name got called out.一つ(ひとつ)おきに席(せき)に着(つ)いてください。
Please leave one seat vacant between you and the next person. (We cannot express this with ごと.)
When we use おき for a longer period (days, weeks, months, etc), we tend to count in the same way as we count lines and people, etc. That is:
一日(いちにち)おきにトイレをそうじします。
I clean the toilet every other day.一週間(いっしゅうかん)おきに 病院(びょういん)に 行(い)きます。
I go to the hospital every second week.
Having said, apparently the number of (young) people who use おき in the same way as ごと is now increasing (although they are still a minority, I believe). So if somebody says something like:
三日(みっか)おきにスーパーに行(い)きます。
Some people understand this to mean: I go to a supermarket every three days and others: I go to a supermarket every 4th day.
So if clarity is important, it is probably best to rephrase above sentences as:
二日(ふつか)に一回(いっかい)トイレをそうじします。
I clean the toilet once every 2 days.
二週間(にしゅうかん)に一回(いっかい)病院(びょういん)に 行(い)きます。
I go to the hospital once every 2 weeks.
三日(みっか)/四日(よっか)に一回(いっかい)スーパーに行(い)きます。
I go to a super market once every 3/4 days.
For more study material for JLPT N4 exam, please visit JLPT N4 Grammar and Vocab and JLPT N4 Kanji pages.
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