How to write with whom, to whom and in which
Short answer: After a preposition, use whom for people and which for things: The friend with whom I traveled is Lan. The room in which we study is warm. Never use who or that right after a preposition. This form is formal; in everyday writing the preposition goes to the end: The boy I gave the book to.
🎯 I can use whom and in which.
At a glance
| Pattern | Use for | Example |
|---|---|---|
| preposition + whom | people | The teacher to whom I spoke was kind. |
| preposition + which | things | The room in which we study is warm. |
| everyday style | preposition at the end | The boy I gave the book to is Ben. |
How to write it
- Find the preposition: to, with, for, in, on.
- Put it before whom (people) or which (things).
- Do not use who or that after the preposition.
- For an everyday text, move the preposition to the end and leave out whom.
Rewrite practice
- Before:
The girl I danced with is my cousin.
After: The girl with whom I danced is my cousin.
Formal version. - Before:
The house we live in is old.
After: The house in which we live is old.
Formal version. - Before:
The man to whom I wrote did not reply.
After: The man I wrote to did not reply.
Everyday version.
Common mistakes
The people to who I spoke were kind.→ The people to whom I spoke were kind.
After a preposition, use whom.The house in that I live is old.→ The house in which I live is old.
Never that after a preposition.The pen with whom I wrote is red.→ The pen with which I wrote is red.
A pen is a thing: which.
Formal and everyday
The formal form puts the preposition first. The everyday form puts it last.
| Formal | Everyday |
|---|---|
| The man with whom I work | The man I work with |
| The room in which we study | The room we study in |
Check yourself
- Choose: “The friend with ___ I traveled.” (who / whom)
Show the answer
whom After a preposition.
- Choose: “The room in ___ we study.” (that / which)
Show the answer
which After a preposition.
- Say it in everyday style: “the boy to whom I gave the book”
Show the answer
the boy I gave the book to Preposition at the end.
Rule cards that help
- whom, to whom, in which: After a preposition use whom for people and which for things. In everyday talk the preposition goes at the end.
Questions
Is whom still used?
In formal writing and speeches, yes. In everyday talk, most people say who or leave it out.
Can I end a sentence with a preposition?
Yes, in everyday English. In formal writing, move it forward.
Where is the rule?
See the rule article on whom, to whom and in which.
Part of 🌉 Because, when, if, who and more (stone 2 of the Learning Path). See also the English writing guide. Đọc bằng tiếng Việt.
Written for English learners by the English for Fun team. How we write our lessons · Last updated 2026-11-05.
Reviewed by Chinh Q. Hoang, PhD, founder, English for Fun · 2026-10-30