What are you driving at?
with:
At what are you driving?
I'm not sure how I would repair Who is Myrtle going out with? since With whom is Myrtle going out? still ends in a preposition (technically it's an adverbial particle, but it sure looks like a preposition to most folks).
So let's just make this clear: "Don't end sentences with prepositions" has always been a dubious rule, and in recent decades has been debunked by everybody who writes about such things. That includes Edward D. Johnson in The Handbook of Good English, Constance Hale in Sin and Syntax: How to Craft Wickedly Effective Prose, Patricia T. O'Conner in Woe Is I: The Grammarphobe's Guide to Better English in Plain English and the undisputed world champion Guru of Grammar, H.W. Fowler, in his Dictionary of Modern English Usage, 2nd Ed.
It seems the rule was created centuries ago by grammarians who tied English unnecessarily to Latin (where it's impossible to end sentences with prepositions). Since prepositions always have objects, they reasoned, the objects should always follow the preposition. But that just makes for some really ugly English.
My favorite quote on this is from Churchill. The story goes that while going over a proof of one of his books, he found a sentence clumsily reworked by an editor who didn't approve of a terminating preposition. In the margin Churchill wrote, "This is the sort of arrant nonsense up with which I will not put."
(This quote varies some. It's likely he wrote "bloody nonsense" and any other versions are simply euphemistic.)
What I find most interesting is how just about everybody ignores this rule in practice, yet almost everybody can quote it. How does a dumb rule that nobody follows survive at all for so long?
