A time preposition is a word that helps to express the relationship between an event or action and a specific time period. We use these prepositions to indicate when something happens, whether it's a specific point in time, a duration, or a relation to another event.

The most used time prepositions, which help us talk about when things happen, include:

1. at - for precise times

2. on - for days and dates

3. in - for months, years, decades, and longer periods

4. since - from a specific time in the past until now

5. for - to specify the duration of time

6. by - indicating a deadline or the latest time by which something should be completed

7. before - earlier than a specific time

8. after - later than a specific time

9. during - throughout the duration of a time period

10. until - up to a certain time

At:

We use "at" to point out when something happens or where it is, making sure we're talking about one specific time or place.

• Time: "Meet me at 5 PM."

  • Here, "at" specifies the exact time for a meeting, focusing on a specific hour of the day.

• Place: "I'll see you at the entrance."

  • In this sentence, "at" shows we're talking about a specific place, the entrance, to tell us where to meet.

On:

We use "on" to specify days and dates, ensuring we're talking about specific days or dates.

• Days: "Let's have lunch on Wednesday."

  • In this example, "on" is used to specify the exact day of the week for the lunch plan.

• Dates: "The conference starts on the 15th of March."

  • Here, "on" identifies the specific date when the conference begins

In:

We use "in" to talk about longer periods of time like months, years, seasons, or parts of the day, helping us pinpoint a more general time frame.

• Months: "My vacation starts in July."

  • In this example, "in" tells us the vacation starts in a certain month, showing it's happening within a bigger time frame, not just on one day.

• Years: "She was born in 1992."

  • Here, "in" tells us the year someone was born, showing it's part of a bigger timeline.

• Seasons: "We're planting trees in the spring."

  • "In" specifies the season when the tree planting will happen, indicating a general time frame within the year.

• Parts of the Day: "I prefer to exercise in the morning."

  • In this case, "in" helps indicate a general part of the day, highlighting a preferred time for an activity.

Since:

We use "since" to indicate the starting point of a period that continues up to the present, focusing on the duration from a specific past time until now.

• Starting Point: "She has been studying since 3 PM."

  • In this example, "since" is used to specify the exact time when she began studying, emphasizing the continuous action from 3 PM up to the current moment.

• Date: "He has lived in New York since 2010."

  • Here, "since" identifies the year he moved to New York, indicating an ongoing situation that started in the past and continues to the present.

For:

We use "for" to talk about the duration of time something lasts, focusing on how long an action or situation has been happening or will happen.

• Duration: "I've been waiting for two hours."

  • In this example, "for" is used to specify how long the waiting has lasted, highlighting the duration of two hours up to the current moment.

By:

We use "by" to indicate a deadline or the latest time by which something needs to be completed, focusing on a point in time that something must happen before.

• Deadline: "The report needs to be finished by Friday."

  • In this example, "by" tells us the report needs to be finished no later than Friday, pointing out the latest time it should be done.

Before:

We use "before" to talk about an event that happens earlier than a specific time or another event, highlighting a sequence where one thing occurs prior to another.

• Sequence: "Please call me before you leave."

  • In this example, "before" asks for a call to be made before someone leaves, showing the call should come first.

After:

We use "after" to indicate that something happens later than a specific time or event, emphasizing a sequence where one thing occurs following another.

• Sequence: "We'll have dessert after dinner."

  • In this example, "after" tells us dessert will come after dinner, showing which comes first and next.

During:

We use "during" to talk about something that happens at some point within a particular period or event, emphasizing that it occurs simultaneously with or throughout the time frame.

• Simultaneous Event: "He fell asleep during the movie."

  • In this example, "during" tells us someone fell asleep while the movie was playing, showing it happened sometime before the movie ended.

Until:

We use "until" to talk about something that continues up to a specific point in time or event, emphasizing that it stops or changes at that moment.

• Continuation: "The library is open until 8 PM."

  • In this example, "until" tells us how late the library is open, showing it stays open for people to visit until it closes at that time.