Prepositions in Wh-Questions
Level B1 · Questions & Auxiliaries
When a wh-question asks about the object of a preposition (who/what someone is talking to, thinking about, waiting for), natural spoken and written English puts the preposition at the end of the question, not before the wh-word. Who are you talking to? is the normal, everyday way to ask this — putting the preposition first, To whom are you talking?, is grammatically correct but sounds extremely formal and old-fashioned in most contexts.
How to build a wh-question with a preposition:
- Identify the preposition the verb or adjective needs, then move the wh-word to the front and leave the preposition at the end, right where it was in the answer: You're waiting for someone → Who are you waiting for?; She's thinking about the trip → What is she thinking about?
- This end-placed preposition still needs do/does/did (or the right auxiliary) for the inversion, exactly like any other wh-question: What are you looking for? (not What you are looking for); Who did she talk to? (not Who talked to she).
- The formal 'preposition + whom' order (To whom, About what, For whom) is used mainly in very formal writing or speech; in everyday English, especially spoken, the preposition almost always goes at the end: Who is this letter for? sounds natural; For whom is this letter? sounds like a formal announcement.
- The same end-placement applies to indirect questions and relative clauses built from the same pattern: I don't know who she's talking to (not to whom she's talking, in everyday speech); the person I'm waiting for (not for whom I'm waiting).
The most common mistake is leaving the preposition attached to the wh-word at the front, imitating a language where this is normal, and producing an unnaturally formal or simply incorrect question in everyday English — About what are you talking? sounds wrong in conversation; natural English asks What are you talking about? A second mistake is forgetting the preposition entirely — Who are you waiting? is incomplete; the verb wait needs for: Who are you waiting for?
Ask what preposition the verb needs when you answer the question with a full sentence (waiting for someone, thinking about something, talking to someone) — then build the question with the wh-word at the front and that same preposition at the very end. If a sentence sounds unnaturally formal with the preposition up front, move it to the end; that's the everyday, natural form.