How to ask a question

Here's a good one from Peter Wood's How to ask a Question:

Weigh the usual interrogatory words in English: who, what, where, why, when. If you can begin your sentence with one of these you are more than half-way to a good question. “Who gave you that scar, Mr. Potter?” “What is a black hole, Mr. Hawking?” “Where is the Celestial City, Mr. Bunyan?” “Why are you wearing that letter, Ms. Prynne?” “When will our troops come home, Mr. Lincoln?”

The rest of his post is worth the read, especially if you want to avoid the most common mistakes even the most intelligent adults make when asking a question. Here's a post I wrote on how question period in K-12 classrooms go wrong.