What Are You Waiting For?

I recently downloaded the back episodes of the Grammar Girl podcast, and last night I listened to an earlier episode about prepositions. I was surprised to learn that the "don't end a sentence with a preposition" rule has passed from rule to debate to acceptable grammar usage. She explains in the podcast that the rule comes from the 16th or 17th Century, and that it was a holdover from correct Latin grammar. "But it's now the 21st centry," she says, and many grammarians now say you can end a sentence with a preposition. Especially if it makes the sentence clearer.

But you still can't use a preposition without an object, so if your sentence ends with a preposition, make sure that the object is somewhere else in the sentence. She uses "Where is the snail race at?" as an example of an object-less preposition.