Prepositions of time and location: “at,” “in,” “on,” and “by”

Estimated reading time: 4 minutes

Prepositions “at,” “in,” “on,” and “by” are all used to indicate time and place. However, there are slight differences in their usage. Understanding how to use these prepositions correctly is important for clear and effective communication.

In today’s NRTC English, I have explained the differences between these common prepositions and provided examples to help you master their usage in everyday language.

“At” to indicate both SPECIFIC times and locations

For example, when referring to time, you might say “at 5 o’clock,” “at noon,” or “at midnight,” indicating specific, precise, or exact points in time. Similarly, “at night” refers to a general time.

When it comes to place, “at” is used for specific locations or spots where something or someone is, such as “at the bus stop,” “at the door,” “at the corner,” or “at the top of the hill.” It can also be used for broader locations like “at school,” “at work,” or “at home.”

For instance, you could say, “We will meet at the park at 3 PM,” which combines both a specific place and a specific time. Another example might be, “She was waiting at the station at 6 o’clock,” or “He found his keys at the bottom of the bag at the end of the day.”

“In” is used with PARTS of the day, months, years, or LONGER PERIODS

When referring to time, the preposition “in” is often used with parts of the day, months, years, or longer periods, such as “in the morning,” “in 2020,” “in the summer,” or “in the 18th century.”

For locations, “in” is used to denote BEING INSIDE A SPACE or WITHING BOUNDARIES, like “in the kitchen,” “in New York,” “in a car,” or “in the park.” For example, “She lives in Ikeja and works in an office” shows how “in” is used to indicate both a city and a type of building.

Other examples include: “He reads the newspaper in the afternoon“; for time “They went on a vacation in 2019“; “The cat is sleeping in the box” and “She enjoys walking in the forest” for place.

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The preposition “on” is used with DAYS and SPECIFIC DATES

The preposition “on” is also used to indicate both time and location. For time, it is often used with days and specific dates, such as “on Monday,” “on New Year’s Day,” “on her birthday,” or “on June 5th.”

Regarding place, “on” denotes being in contact with a surface or in a position above but touching something, like “on the table,” “on the bus,” “on the wall,” or “on the roof.” For example, “He left his book on the desk on Tuesday” shows how “on” is used to indicate both a specific surface and a specific day.

Other examples include “We have a meeting on Friday” and “She went to a party on Christmas Eve” for time, and “The keys are on the counter” and “He sat on the bench” for place.

However, the preposition “by” is used to indicate DEADLINES and PROXIMITY

When used for time, it often signifies a deadline, such as in “by 5 o’clock,” “by tomorrow,” “by next week,” or “by the end of the day.” For example, “Please submit the report by 5 o’clock” means the report should be submitted no later than 5 o’clock.

When used for location, “by” denotes proximity to a place, as in “by the lake,” “by the door,” “by the window,” or “by the park.” For instance, “She was waiting by the door” indicates she was positioned next to or near the door.

In these contexts, “by” is commonly used and understood to indicate deadlines or proximity.

Understanding the differences between prepositions of time and location—”at,” “in,” “on,” and “by”—is crucial for mastering the nuances of English grammar.

Each preposition serves a specific purpose and conveys distinct meanings that can significantly impact the clarity of your communication. “At” typically denotes a precise point in time or place, “in” suggests a broader, enclosed space or time period, “on” refers to specific surfaces or dates, and “by” often indicates proximity or a deadline.

Mastery of these prepositions of time and location enhances both written and spoken expression, ensuring that your message is conveyed accurately and effectively. Whether you’re drafting a formal report or engaging in casual conversation, a clear understanding of these prepositional nuances will enrich your communication skills and contribute to more precise and coherent interactions.