There are certain grammar myths out there that can make even the best writers go bad. English teachers have learned how to strike fear into the hearts of their students, but there's no reason you should be afraid of prepositions. It's time to find out the truth about the proper way to use prepositions in your writing.
Remember the rule? A preposition is anywhere a mouse can go. This includes words like from, under, to, above, as, into, out, through and on -- to name just a few. Prepositions are one of the most-used elements of the English language...and they're used to invoke terror in the minds of writers everywhere.
It's a commonly-accepted rule of English, and writing in general, that it's simply not okay to end a sentence with a preposition. This rule renders such common expressions as "what's going on?" and "what's up?" inherently flawed, not to mention renders oft-heard phrases like "what is that from?" and "what's that for?" all but useless.
If I was going to make the above proper, according to the preposition rule, those phrases would read read more like "from what is that?" and "for what is that?" And doesn't that sound absolutely outlandish? Who speaks like that, except for people in old Shakespearean plays? Throw around enough "that which" and "where from" into your book, and it's going to sound like you were born back in the 18th century.
This is my long way of saying the rule is bunk. In common English today, pretty much everyone ends their sentences with prepositions every single day. If you want to be Polly Perfect and make your grammar spot-on throughout your prose, you don't have to end your sentences with prepositions if you don't want to -- up to a point. But when you're writing dialogue, none of those stuffy old rules apply. The only rule that really matters in dialogue-writing is this: write it the way people talk. I've never heard anyone ask me "for whom is that gift?" and I sure as heck don't expect to read it in a contemporary book, unless the character in question is some sort of rigid English professor.
Prepositions aren't scary...only grammar rules that aren't really rules, and don't really make any sense. So the next time you're getting ready to work a sentence around to shove a to in the front instead of the back, stop and ask yourself if it's really an improvement. If it sounds right and flows naturally, stick your prepositions wherever you like.