Preposition of Agent: Definition, Examples & Rules | English Grammar
Last Updated: 01 Jul, 2025
Welcome! In this lesson, you'll learn all about Prepositions of Agents or Things in English grammar. We'll cover what they are, provide a complete list, and show you how to use them correctly. You'll find real-life examples, a quick quiz, and pro tips to help you master this essential grammar topic.
What are Prepositions of Agents or Things?
Preposition of Agent Definition: A preposition of agent shows who or what performs an action or causes something to happen. Common prepositions of agent include by, with, from, through, and via.
Why are Prepositions of Agents Important? They help us identify who does something, what causes an action, or what instrument is used to perform an action.
Function in Grammar
Prepositions of agents or things show relationships between actions and their performers or instruments:
- Agent: The book was written by Shakespeare. (who did it)
- Instrument: She cut the paper with scissors. (what was used)
- Source: The gift came from my aunt. (where it originated)
Agent vs Instrument vs Source
| Type | Preposition | Example |
|---|---|---|
| Agent (Who) | by | written by the author |
| Instrument (With what) | with | cut with a knife |
| Source (From where) | from | came from the store |
| Means (How) | through/via | sent through email |
Each type shows a different relationship between the action and its performer or cause.
📌 Agent Preposition Challenge!
Can you identify the prepositions of agents or things?
- The book was written by Shakespeare.
- She cut the paper with scissors.
- The gift came from my aunt.
Show Answers
- by (agent)
- with (instrument)
- from (source)
Examples in Sentences
- The book was written by Shakespeare.
- She cut the paper with scissors.
- The gift came from my aunt.
- The message was sent through email.
- The painting was created by a famous artist.
- He opened the door with a key.
- The package arrived from China.
- We traveled via train.
- The house was built by skilled workers.
- She wrote the letter with a pen.
Complete List of Agent/Thing Prepositions
Agent Prepositions (Who performs):
- by - shows who performs an action (written by the author)
- from - shows source or origin (heard from a friend)
Instrument Prepositions (What is used):
- with - shows tool or instrument (cut with a knife)
- by - shows method or means (travel by car)
- through - shows means or medium (learn through practice)
- via - shows route or method (sent via email)
Source Prepositions (Where from):
- from - shows origin or source (came from the store)
- of - shows origin or composition (made of wood)
- out of - shows material or source (carved out of stone)
Common Usage Patterns
| Preposition | Usage | Examples |
|---|---|---|
| BY | Agent, method | written by, travel by |
| WITH | Instrument, tool | cut with, write with |
| FROM | Source, origin | came from, heard from |
| THROUGH | Means, medium | through practice, through email |
| VIA | Route, method | via train, via internet |
| OF | Material, composition | made of, full of |
Each preposition has specific uses for different types of relationships.
Special Rules and Notes
- BY vs WITH: BY shows agent or method, WITH shows instrument or tool.
- Passive Voice: Use BY to show who performs the action in passive sentences.
- Transportation: Use BY for means of transport (by car, by plane).
- Materials: Use OF for what something is made from (made of wood).
- Communication: Use THROUGH or VIA for methods of communication.
Common Mistakes to Avoid
- Confusing BY and WITH: Say "cut with a knife" not "cut by a knife."
- Wrong Agent Preposition: Use "by" for who did it, not "from."
- Missing Prepositions: Don't forget prepositions in passive voice.
- Overusing FROM: Not everything comes "from" - sometimes use "by" or "with."
Quick Quiz: Choose the Correct Preposition!
Which preposition fits best in these sentences?
- The book was written ___ Shakespeare.
- She cut the paper ___ scissors.
- The gift came ___ my aunt.
- We traveled ___ train.
- The table is made ___ wood.
Answers: by, with, from, by, of
Practice Exercises
Exercise 1: Agent, Instrument, or Source?
Identify what each preposition shows:
- The song was sung by the choir.
- He fixed it with a hammer.
- The letter came from my sister.
- She painted with watercolors.
- The story was told by my grandmother.
Show Answers
- Agent (who sang)
- Instrument (what tool)
- Source (where from)
- Instrument (what medium)
- Agent (who told)
Exercise 2: Fill in the Blanks
Complete with appropriate prepositions:
- The house was built ___ skilled workers.
- She opened the box ___ a key.
- The package arrived ___ overseas.
- We communicated ___ email.
- The sculpture is made ___ marble.
Show Answers
- by
- with
- from
- through/via
- of
Frequently Asked Questions
What is a preposition of agent?
A preposition of agent shows who or what performs an action, especially in passive voice sentences. Common prepositions of agent include by, with, through, and from.
How do you use "by" as a preposition of agent?
Use "by" to show who performs an action in passive voice: "The book was written by the author." "By" indicates the person or thing that does the action.
What is the difference between "by" and "with" as prepositions of agent?
"By" shows the doer of an action (by the teacher), while "with" shows the instrument or tool used (with a pen, with a hammer).
Can you give examples of prepositions of agent in sentences?
Yes! Examples: The painting was created by the artist. The door was opened with a key. The message was sent through email. The idea came from experience.
When do you use prepositions of agent?
Prepositions of agent are commonly used in passive voice constructions to show who or what causes an action, and to indicate the means or instrument used.
What are common prepositions of agent?
Common prepositions of agent include: by (the doer), with (the instrument), through (the means), from (the source), and via (the method).
How do prepositions of agent work in passive voice?
In passive voice, prepositions of agent identify who performs the action: "The cake was baked by mom" (active: "Mom baked the cake").
What is the difference between agent and instrument?
An agent is who does the action (by the doctor), while an instrument is what is used to do the action (with a scalpel). Both use prepositions of agent.
Conclusion
Prepositions of agents or things help us identify who performs actions, what tools are used, and where things come from. Remember: BY for agents, WITH for instruments, FROM for sources!