PREPOSITIONS AT THE END OF QUESTIONS

When a question word is the object of a preposition, the preposition usually comes at the end of the clause, especially in an informal style.

• What are you looking for? (More natural than ‘For what are looking?’)
• Who is this present for? (For whom is this present? is extremely formal.)
• Who were you speaking to? (NOT To whom were you speaking?)
• Which pictures are you talking about?
• What are you laughing at?
• Who put the cat in?
• Who turned the lights off?

Prepositions come at the end of clauses in indirect wh-questions and what-clauses which are not questions.

Tell me what you are looking for. (NOT Tell me for what you are looking.)

What a lot of trouble I have gotten into! (NOT Into what a lot of trouble I have gotten.)

Some questions consist of simply a question word and preposition.

• What with?
• Who for?
• What about?

Note that this structure is unusual when there is a noun with the question word.

With what money? (NOT What money with?)

Exercise

Fill in the blanks with appropriate prepositions.

1. What are you crying ————–?
2. Who shall I give this ——————?
3. What are you waiting ——————?
4. Which writer were you talking ——————?
5. Which candidate have you voted ——————-?

Answers

1. for
2. to
3. for
4. about
5. for

http://www.englishpractice.com/grammar/prepositions-questions/