"in"with"on"Both are prepositions that denote time, but they have some differences in usage. Here's a detailed explanation of their differences and usage:
1. "in"Indicates a period of time:
in"Followed by a period of time to indicate a time range, time period, or the end of a time period, for example:
i'll be on vacation in july.(I'll be on vacation in July.) ）
the project is due in two weeks.(This project will be completed in two weeks.) ）
she will graduate in three years.(She will graduate in three years.) ）
in"It can also indicate how much after or how long ago and is used in the question:
he will be back in 10 minutes.(He'll be back in 10 minutes.) ）
2. "on"Indicates a specific day, day of the week, or holiday:
on"It is followed by a specific day, day of the week, or festival to indicate a specific day or day of the week, for example
the meeting is on monday.(The meeting is scheduled for Monday.) ）
we celebrate christmas on december 25th.(We celebrate Christmas on December 25th.) ）
the concert will be held on new year's eve.(*The meeting will be held on Chinese New Year's Eve.) ）
3.Precautions:
For some special cases, it can be used at the same time"in"with"on"：
he arrived in california on july 4th.(He arrived in California on July 4.) ）
Year and season are usually used"in"：
they got married in 2010.(They got married in 2010.) ）
we enjoy skiing in winter.(We love skiing in the winter.) ）
on"It can also be expressed at a specific time:
we h**e a meeting on monday at 10 a.m.(We have a meeting on Monday at 10 a.m.) ）
in"It is usually used to indicate a time period, a time range, how much after or how much before"on"It is used to indicate a specific date, day of the week, or holiday. However, there are times when specific phrases and phrases may need to be used accordingly according to idiomatic expressions. Hopefully, the above explanations will help you better understand and apply"in"with"on"。