at: for a precise time.
in: for months, years, centuries and long periods.
on: for days and dates.
When we want to talk about time, specify dates, parts of days, whole days or longer periods of time, we need what we call (temporal prepositions) prepositions of time .

During: We use during +noun to say when something happens.

For: We use for + a period of time.
Since: We use since + a period of time.
Until: We use until/till to say how long a situation continues.
From-To: We use from – to +beginning and end of a period.
    • I have a class at 9 am.
    • In Morocco, it always snows in November.
    • Do you study on Mondays?
    • Last evening we watched a TV show from 2 to 8 o’clock.
    • Let’s wait until he brings the car to the front door.
    • They have known each other since they were at the kindergarten.
    • I worked with the Japanese partners for seventeen years.
  • We met a lot of interesting people during our trip.

When we say last, next, every, this we do not also use at, in, on.

  • I went to London last year. (not in last year)
  • He’s coming back next Friday. (not on next Friday)
  • I go home every weekend. (not at every weekend)
  • We’ll call you this evening. (not in this evening)