on and at in english

简单法则:

  • on 后跟 date
  • at 后跟 datetime

We use:

  • at for a PRECISE TIME
  • in for MONTHS, YEARS, CENTURIES and LONG PERIODS
  • on for DAYS and DATES

Resources

https://www.englishclub.com/grammar/prepositions-at-in-on-time.htm