โดย
By: Agent and Method
In the displayed examples, โดย names the editor or scientist, identifies train travel, or occurs in a request for prompt sending. Interpret the full phrase rather than applying one English “by” gloss everywhere.
How It Works
1. Naming an Agent
บทความนี้เขียนโดยบรรณาธิการ names the editor after โดย. ทฤษฎีนี้ถูกค้นพบโดยนักวิทยาศาสตร์ชาวไทย contains ถูก before ค้นพบ and names a Thai scientist after โดย. These displayed constructions do not establish that every passive needs โดย or that it removes an adverse meaning. Compare ได้รับ in its own complete receiving constructions and topic followed by comment as a separate way to organize a sentence; neither comparison proves that the displayed โดย clauses are imported or unnatural.
2. Transport and Method
เดินทางโดยรถไฟ identifies train travel. NIU’s selected โดย entry gives plane travel and an action done with permission. Read these full phrases rather than deriving an agent-only rule. The first exercise requests เขาเขียนด้วยปากกา, using ด้วย in the displayed pen-instrument construction; it does not declare every use of โดย with a method or tool impossible.
3. Adverbial Expressions
กรุณาส่งเอกสารโดยเร็ว asks for prompt sending. The third exercise instead requests เขาวิ่งอย่างเร็ว with อย่าง describing the running manner. เขาวิ่งโดยเร็ว can have a contextual reading, such as prompt action, and is not universally ungrammatical. Read expressions such as โดยเฉพาะ and โดยปกติ as complete expressions; their presence does not give a general rule that every adjective can follow โดย or a fixed register ranking.
4. Clauses with โดยที่
NIU’s selected โดยที่ entry gives full clauses containing โดยที่ไม่, translated with “without,” including leaving without telling anyone. Interpret the negation and surrounding clause together. Compare ทั้ง ๆ ที่ and ถึงแม้ว่า in their own contrasting clauses; an English concessive paraphrase in a particular context does not make these constructions interchangeable in every sentence.
5. The Requested Passive Task
The second exercise requests ฉันถูกหมากัด, placing หมา between ถูก and กัด. ฉันถูกกัดโดยหมา can also express a dog as the biting agent. The exercise asks for the displayed shorter sequence, not a ban on meaningful alternatives or a claim about English influence. The royal-writing example is an attribution phrase, not proof of a particular work, date, or real author.
Examples (5)
- บทความนี้เขียนโดยบรรณาธิการ
This article was written by the editor.
Word by Word: article | this | written | by | editor
โดยบรรณาธิการ names the editor as writer in this example. The English selects a past interpretation; the native clause has no overt past marker and does not verify an actual article or a register frequency.
- ทฤษฎีนี้ถูกค้นพบโดยนักวิทยาศาสตร์ชาวไทย
This theory was discovered by a Thai scientist.
Word by Word: theory | this | ถูก [passive marker] | discovered | by | Thai scientist
Here ถูก precedes the discovery verb and โดย introduces the scientist. The example illustrates this sequence; it does not require it for every passive or assert a real discovery.
- กรุณาส่งเอกสารโดยเร็ว
Please send the document promptly.
Word by Word: please | send | document | โดยเร็ว [promptly here]
โดยเร็ว is read as requesting prompt sending here. The native does not force plural documents or prove that every โดย adverb is confined to formal writing.
- เดินทางโดยรถไฟ
Travel by train.
Word by Word: travel | by | train
โดยรถไฟ identifies the means of travel in this phrase. No subject, date, or rule excluding other registers is expressed.
- พระราชนิพนธ์โดยพระบาทสมเด็จพระเจ้าอยู่หัว
A royal composition by His Majesty the King.
Word by Word: royal composition | by | His Majesty the King [royal title]
This is an attribution phrase containing royal vocabulary, not an explicitly past finite clause. The wording names no particular work or current individual and does not establish the most formal possible use of โดย.
Common Mistakes
Not reproducing the requested pen phrase with ด้วย.
เขาเขียนโดยปากกาเขาเขียนด้วยปากกาThe task requests เขาเขียนด้วยปากกา with ด้วย naming the pen as instrument. เขาเขียนโดยปากกา does not reproduce that requested construction; this task does not establish a universal instrument-versus-method ban.
Not reproducing the requested ถูก + agent + verb sequence.
ฉันถูกกัดโดยหมาฉันถูกหมากัดThe task requests ฉันถูกหมากัด, with หมา directly after ถูก. ฉันถูกกัดโดยหมา can also express being bitten by a dog. It is a meaningful alternative, not generally invalid or proof of a clumsy English translation.
Not reproducing the requested running-manner phrase with อย่าง.
เขาวิ่งโดยเร็วเขาวิ่งอย่างเร็วThe task requests เขาวิ่งอย่างเร็ว with อย่าง. เขาวิ่งโดยเร็ว can be interpreted in context, for example as running promptly; the task does not ban every everyday use of โดยเร็ว.
How It Connects
Learn This First
To understand 'โดย' as a formal agent marker, you first need to be comfortable with basic Thai sentence structure and how the passive voice is generally formed. Since 'โดย' is primarily used in formal writing or speech, familiarity with other formal markers helps provide the necessary context for its usage.
- ถูกHad It Done to You
One job of โดย is naming who did an action, as in a formal ถูก passive. Another job, naming a method (เดินทางโดยรถไฟ, travel by train), needs no passive, so this link matters mainly for the agent use.
Level 2 - และAnd — Formal Link
โดย is often used in formal contexts, similar to the formal conjunction 'และ', and requires familiarity with formal sentence structures.
Level 1
Related Patterns
- ด้วยToo and with
Compare the requested ด้วยปากกา instrument phrase with the displayed โดยรถไฟ transport phrase, without deriving an exclusive rule for every method.
Level 1 - อย่าง + AdjectiveMaking an Adverb
Compare the requested อย่างเร็ว running phrase with โดยเร็ว in the sending request; interpret each full context.
Level 3 - ทั้ง ๆ ที่Even Though
Compare complete contrasting clauses with ทั้ง ๆ ที่ and the selected โดยที่ไม่ clauses translated with “without.”
Level 3 - ถึงแม้ว่าConcession with ถึงแม้ว่า
Read ถึงแม้ว่า in its own contrasting clause rather than replacing every โดยที่ clause with it.
Level 3 - Topic Then Comment
Topic followed by comment is a separate sentence-organizing pattern, not evidence that the displayed โดย clauses are unnatural or imported.
Foundations
Learn Next
Patterns that build on this one.
Words in This Pattern
Practice โดย in Bubblegum
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