Mastering Prepositions: In, On, and Under

Prepositions are essential components of the English language, acting as bridges that connect nouns or pronouns to other words in a sentence. Among the most common and versatile prepositions are in, on, and under. Understanding how to use these prepositions correctly is crucial for clear and accurate communication. This article provides a comprehensive guide to mastering the usage of in, on, and under, covering their definitions, functions, examples, common mistakes, and practice exercises. Whether you are a beginner or an advanced learner, this guide will help you improve your understanding and use of these fundamental prepositions.

Table of Contents

• Definition of Prepositions: In, On, and Under
• Structural Breakdown
• Types and Categories of Usage
  • Location and Space
  • Time
  • State or Condition
• Examples of Prepositions in Use
  • Examples for Location and Space
  • Examples for Time
  • Examples for State or Condition
• Usage Rules
• Common Mistakes
• Practice Exercises
  • Exercise 1: Fill in the Blanks
  • Exercise 2: Error Correction
  • Exercise 3: Sentence Construction
• Advanced Topics
  • Idiomatic Expressions
  • Prepositional Phrases
• FAQ
• Conclusion

Definition of Prepositions: In, On, and Under

A preposition is a word that connects a noun or pronoun (the object of the preposition) to another word in a sentence. This connection often indicates relationships such as location, direction, time, or manner. The prepositions in, on, and under are particularly useful for describing spatial relationships and, to a lesser extent, temporal relationships.

In generally indicates enclosure or containment within a space, area, or volume. It can also refer to being part of a group or category, or a point in time within a larger period.

On typically denotes a surface or a position directly above and touching a surface. It can also indicate a specific date or day, or a state of being supported by something.

Under signifies a position directly below something, usually covered or protected by it. It can also mean subject to a rule or authority.

Structural Breakdown

The basic structure involving prepositions is: Preposition + Noun/Pronoun (Object of the Preposition). This combination forms a prepositional phrase, which can function as an adjective or adverb, modifying other words in the sentence.

For example:

• In the box (in + box)
• On the table (on + table)
• Under the bed (under + bed)

These prepositional phrases provide information about where something is located. The preposition specifies the relationship between the object (e.g., box, table, bed) and another element in the sentence.

Types and Categories of Usage

The prepositions in, on, and under can be categorized based on their primary uses, which include location and space, time, and state or condition.

Location and Space

This is the most common use of these prepositions. They describe the physical position of something relative to another object or area.

In: Indicates that something is enclosed or surrounded. For example, “The keys are in my pocket.”

On: Indicates that something is on a surface. For example, “The book is on the desk.”

Under: Indicates that something is below something else. For example, “The cat is under the chair.”

Time

These prepositions can also be used to indicate when something happens.

In: Used with months, years, centuries, and periods of time. For example, “I was born in 1990.”

On: Used with days and dates. For example, “The meeting is on Monday.”

State or Condition

In certain contexts, these prepositions can describe a state or condition.

In: Can indicate a state of being, such as “in love” or “in trouble.”

On: Can indicate a state of activity, such as “on duty” or “on vacation.”

Under: Can indicate a state of being controlled or influenced, such as “under pressure” or “under investigation.”

Examples of Prepositions in Use

To further illustrate the usage of in, on, and under, here are extensive examples categorized by their primary function.

Examples for Location and Space

The following table provides examples of in, on, and under used to describe location and space. These examples cover a wide range of scenarios to illustrate the nuanced usage of each preposition.

Preposition	Example Sentence
In	The money is in the safe.
In	She lives in New York City.
In	The letter is in an envelope.
In	The fish swims in the ocean.
In	The children are playing in the garden.
In	My phone is in my bag.
In	We are in a meeting right now.
In	The bird is in its nest.
In	The cookies are in the jar.
In	He works in a bank.
On	The book is on the shelf.
On	The picture is on the wall.
On	The cat is sitting on the roof.
On	The food is on the table.
On	There’s a stain on my shirt.
On	The news is on TV.
On	The island is on the map.
On	He depends on his parents for support.
On	The responsibility is on you.
On	The concert is on the beach.
Under	The cat is hiding under the bed.
Under	The treasure is buried under the ground.
Under	The dog is lying under the tree.
Under	There’s a tunnel under the river.
Under	The secret is under wraps.
Under	The project is under construction.
Under	The troops are under attack.
Under	The company is under new management.
Under	The city is under a curfew.
Under	The document is under review.

Examples for Time

The following table provides examples of in and on used to indicate time. Note that under is not typically used in temporal contexts.

Preposition	Example Sentence
In	I was born in May.
In	The event will take place in the summer.
In	She graduated in 2010.
In	He finished the race in record time.
In	They will arrive in an hour.
In	The project must be completed in three weeks.
In	The store is open in the morning.
In	I like to read in the evening.
In	We met in the past.
In	The changes will occur in the future.
On	The meeting is on Monday.
On	Her birthday is on July 4th.
On	The accident happened on a rainy day.
On	They celebrate Christmas on December 25th.
On	The store is closed on Sundays.
On	He always arrives on time.
On	The project is due on Friday.
On	The train leaves on the hour.
On	The tradition continues on this day.
On	The schedule is effective on January 1st.

Examples for State or Condition

The following table presents examples of in, on, and under used to describe a state or condition. These examples showcase how these prepositions can convey abstract relationships and circumstances.

Preposition	Example Sentence
In	They are deeply in love.
In	He is in trouble with the law.
In	She is in a good mood today.
In	The company is in debt.
In	He is in a state of confusion.
In	The project is in progress.
In	She is in charge of the department.
In	He is in agreement with the proposal.
In	The information is in demand.
In	The product is in stock.
On	She is on vacation.
On	He is on duty.
On	The machine is on standby.
On	She is on a diet.
On	The house is on fire.
On	He is on a mission.
On	The project is on schedule.
On	The sale is on now.
On	The pressure is on him.
On	The decision is on hold.
Under	They are living under difficult circumstances.
Under	The project is under investigation.
Under	He is working under pressure.
Under	The city is under lockdown.
Under	The contract is under review.
Under	The situation is under control.
Under	The students are under the guidance of the teacher.
Under	The country is under a new government.
Under	The information is under embargo.
Under	The deal is under negotiation.

Usage Rules

While the general definitions of in, on, and under provide a solid foundation, there are specific usage rules and nuances to consider for accurate and effective communication.

In:

• Use in for enclosed spaces, such as rooms, buildings, and containers.
• Use in for geographical locations like cities, countries, and regions.
• Use in for periods of time, such as months, years, and centuries.
• Use in for states or conditions, such as “in love” or “in trouble.”

On:

• Use on for surfaces, such as tables, walls, and floors.
• Use on for specific dates and days.
• Use on for means of transportation when you can walk around, such as “on a bus” or “on a plane.”
• Use on for electronic devices, such as “on the phone” or “on TV.”

Under:

• Use under for positions directly below something.
• Use under for being controlled or influenced by something.
• Use under for being subject to a rule or authority.

Common Mistakes

Even experienced English speakers sometimes make mistakes when using in, on, and under. Here are some common errors and their corrections.

Incorrect	Correct	Explanation
The book is in the table.	The book is on the table.	Books are typically placed on a surface, not enclosed within it.
I live on France.	I live in France.	Use in for countries and large geographical areas.
The cat is on the bed.	The cat is under the bed.	This depends on the cat’s location. If it’s below the bed it is ‘under’. If on the surface, ‘on’.
See you on Monday morning.	See you in Monday morning.	Use ‘on’ for specific days.
He is on love.	He is in love.	The correct idiom is “in love.”
She is in duty.	She is on duty.	The correct idiom is “on duty.”

Practice Exercises

To reinforce your understanding of in, on, and under, complete the following exercises.

Exercise 1: Fill in the Blanks

Fill in the blanks with the correct preposition (in, on, or under).

Question	Answer
1. The keys are ______ my pocket.	in
2. The picture is ______ the wall.	on
3. The cat is sleeping ______ the chair.	under
4. I was born ______ 1995.	in
5. The meeting is ______ Friday.	on
6. She is ______ vacation.	on
7. He is ______ trouble with the police.	in
8. The book is ______ the shelf.	on
9. The treasure is buried ______ the ground.	under
10. They live ______ London.	in

Exercise 2: Error Correction

Identify and correct the errors in the following sentences.

Incorrect Sentence	Correct Sentence
1. The food is in the table.	The food is on the table.
2. I live on Italy.	I live in Italy.
3. The lamp is under the desk.	The lamp is on the desk.
4. See you in Tuesday.	See you on Tuesday.
5. He is on a good mood.	He is in a good mood.
6. She is in duty today.	She is on duty today.
7. The dog is on the tree.	The dog is in the tree.
8. The paper is under the wall.	The paper is on the wall.
9. The office is on the second floor.	The office is on the second floor.
10. The concert is in next week.	The concert is on next week.

Exercise 3: Sentence Construction

Create sentences using in, on, and under based on the given prompts.

Prompt	Example Sentence
1. The cat and the couch	The cat is sleeping on the couch.
2. The documents and the file cabinet	The documents are in the file cabinet.
3. The car and the bridge	The car is under the bridge.
4. The party and Saturday	The party is on Saturday.
5. The children and the playground	The children are playing in the playground.
6. The painting and the wall	The painting is on the wall.
7. The secret and the lock	The secret is under lock and key.
8. The meeting and July	The meeting is in July.
9. The city and the river	The city is on the river.
10. The information and the report	The information is in the report.

Advanced Topics

For advanced learners, understanding the nuances of idiomatic expressions and prepositional phrases involving in, on, and under can further enhance their proficiency.

Idiomatic Expressions

Idiomatic expressions are phrases whose meaning cannot be understood from the literal meanings of the individual words. Many idioms use prepositions, and it’s essential to learn them as fixed expressions.

• In a nutshell: Briefly or in summary.
• On the ball: Alert, competent, and efficient.
• Under the weather: Feeling unwell.
• In the long run: Over a long period of time.
• On cloud nine: Extremely happy.
• Under pressure: Experiencing stress or difficulty.

Prepositional Phrases

Prepositional phrases consist of a preposition and its object, functioning as adjectives or adverbs to modify other words in the sentence. Recognizing and using prepositional phrases correctly can improve sentence structure and clarity.

• In accordance with: Following the rules or guidelines.
• On behalf of: Representing someone else.
• Under the circumstances: Given the current situation.
• In addition to: Besides or as well as.
• On the contrary: Actually, the opposite is true.
• Under consideration: Being thought about or evaluated.

FAQ

Here are some frequently asked questions about using in, on, and under.

1. When should I use in versus on for locations?

   Use in for enclosed spaces (e.g., “in the room”) and larger areas (e.g., “in the city”). Use on for surfaces (e.g., “on the table”) and specific locations along a route (e.g., “on the way”).

2. How do I know when to use on for dates versus in for months?

   Use on for specific dates (e.g., “on July 4th”) and days of the week (e.g., “on Monday”). Use in for months (e.g., “in July”) and years (e.g., “in 2023”).

3. Can under be used in contexts other than physical location?

   Yes, under can be used to describe a state of being controlled or influenced (e.g., “under pressure”) or subject to a rule (e.g., “under investigation”).

4. Are there any exceptions to the general rules for these prepositions?

   Yes, idiomatic expressions often deviate from the general rules. For example, we say “on the phone” even though the phone isn’t necessarily a surface.

5. How can I improve my understanding of these prepositions?

   Practice regularly by completing exercises, paying attention to how native speakers use these prepositions, and looking up any unfamiliar usages in a dictionary.

6. What is the difference between “in time” and “on time”?

   “In time” means early enough or before the deadline, whereas “on time” means at the exact scheduled time. For example, “I arrived in time for the meeting” means you arrived before it started. “I arrived on time for the meeting” means you arrived exactly when it was scheduled to begin.

7. Why do we say “on the bus” but “in the car”?

   This is largely idiomatic. Generally, “on” is used for larger vehicles where you can walk around (like a bus, train, or plane), while “in” is used for smaller, more enclosed vehicles (like a car or taxi).

8. Is it correct to say “underneath” instead of “under”?

   Yes, “underneath” is often interchangeable with “under,” but it usually emphasizes the covering or concealment aspect more strongly. For example, “The cat is underneath the blanket” suggests the blanket is covering the cat more explicitly than “The cat is under the blanket.”

Conclusion

Mastering the prepositions in, on, and under is essential for clear and accurate communication in English. These prepositions are fundamental for describing location, time, and various states or conditions. By understanding their definitions, usage rules, and common exceptions, you can significantly improve your English proficiency. Remember to practice regularly, pay attention to context, and be aware of idiomatic expressions to avoid common mistakes. With consistent effort, you can confidently and effectively use these prepositions in your daily communication.

Continue practicing with different exercises and real-life examples to solidify your understanding. Pay close attention to how native speakers use these prepositions in various contexts. By doing so, you’ll develop a strong intuition for their correct usage and enhance your overall fluency in English.