Prepositions of time in English grammar are words that indicate when something happens. They provide specific details about the timing of an action or event. The most commonly used prepositions of time include "at," "on," and "in," among others. Here’s a detailed guide on how to use these prepositions correctly:

1. Preposition "At"

"At" is used to specify a precise time or a specific point in time.

a. Specific Times:

  • Examples:
    • The meeting starts at 3:00 PM.
    • He usually goes to bed at midnight.

b. Mealtime:

  • Examples:
    • We’ll meet at lunchtime.
    • She’s busy at dinner.

c. Holidays and Festivals (without "day" or "night"):

  • Examples:
    • They visit their family at Christmas.
    • At Easter, many people attend church services.
d. Expressions:
    • Examples:
      • At the moment (e.g., She’s not available at the moment.)
      • At present (e.g., At present, I’m living in London.)
      • At night (e.g., The stars shine brightly at night.)

2. Preposition "On"

"On" is used to refer to specific days and dates.

a. Days of the Week:

  • Examples:
    • I have a meeting on Monday.
    • We’re going out on Saturday.

b. Dates:

  • Examples:
    • The event is on July 4th.
    • She was born on March 15th.

c. Special Days:

  • Examples:
    • We celebrate on New Year’s Eve.
    • They got married on Valentine’s Day.
c. Expressions:
    • Examples:
      • On time (e.g., Please be on time.)
      • On a holiday (e.g., We’re going to the beach on our holiday.)

3. Preposition "In"

"In" is used for more general periods of time, such as months, years, centuries, and long periods.

a. Months:

  • Examples:
    • She will visit us in September.
    • The course starts in January.

b. Years:

  • Examples:
    • He graduated in 2010.
    • In 1995, the company was founded.

c. Decades and Centuries:

  • Examples:
    • Jazz music became popular in the 1920s.
    • Many technological advancements occurred in the 19th century.

d. Seasons:

  • Examples:
    • We go skiing in winter.
    • The flowers bloom in spring.

e. Parts of the Day:

  • Examples:
    • She exercises in the morning.
    • In the afternoon, I usually take a nap.

f. Longer Periods:

  • Examples:
    • The project will be completed in a few weeks.
    • He’ll be back in a moment.


4. Other Prepositions of Time

a. "During": Used to indicate that something happens within a particular period.

  • Examples:
    • She was very productive during the summer.
    • We stayed indoors during the storm.

b. "By": Used to indicate a deadline or the latest time something can happen.

  • Examples:
    • Please submit your report by Friday.
    • We need to finish this by the end of the day.

c. "For": Used to indicate the duration of an action or event.

  • Examples:
    • I’ve lived here for five years.
    • She studied for two hours.

d. "Since": Used to indicate the starting point of an action that continues up to the present.

  • Examples:
    • I’ve known him since 2012.
    • She has been working here since last month.

e. "Until" (or "Till"): Used to indicate the end point of an action or event.

  • Examples:
    • I’ll wait until you arrive.
    • The store is open till 9 PM.
f. "From...to": Used to show the beginning and end of a time period.
  • Examples:
    • We lived there from 2001 to 2005.



Summary of Prepositions of Time

Preposition Usage Examples
At Specific times, mealtime, holidays At 5:00 PM, at noon, at Christmas
On Days, dates, specific days On Monday, on July 4th, on her birthday
In Months, years, seasons, parts of day In June, in 1990, in the morning
During Periods of time within an event During the summer, during the meeting
By Deadlines, latest time By Friday, by 6 PM
For Duration of time For two hours, for five years
Since Starting point continuing to present Since 2005, since last week
Until (Till) End point of an action Until midnight, till the end of the movie
From...to Start and end time From 8 AM to 4 PM, from January to March

Conclusion

Prepositions of time are essential for indicating when events occur. By mastering the use of "at," "on," "in," and other prepositions of time, you can convey precise information about timing in your speech and writing. Understanding the differences between these prepositions will help you use them correctly in various contexts, enhancing the clarity and accuracy of your communication.