Do you know how to punctuate every kind of question?
Statements with Tag Questions
Now, what about those little questions that come at the end of a statement? You didn't forget my birthday, did you? It's fun to play marimbas, isn't it?
Bits like did you and isn't it are called tag questions and they turn the whole sentence into a question, so use a question mark at the end (4).
Do you have a curious nature? Do you wonder about things? When you wonder, your statements might sound like questions, but they're not direct questions, they're indirect questions, and they don't take a question mark. For example, I wonder why he went to the store. It's an indirect question—essentially a statement—so there's no question mark. I wonder if Squiggly would loan me his marimbas. Again, it's not a question.
Questions in Quotation Marks
Next, where do you put the question mark when you're using quotation marks? It depends on the sentence—is the whole thing a big question, or is only the part in quotation marks a question?
If the whole sentence is a question, then you put the question mark outside the quotation mark (1, 5). Here's an example: What do you think Squiggly meant when he said, “The fish swam darkly up the river”? The whole sentence is a question, so the question mark goes at the very end (outside the quotation mark).
On the other hand, if only the quotation is a question, then the question mark goes inside the quotation mark (1, 5). Here's an example: Squiggly ran up to Aardvark and asked, "Where are the fish?" The question mark goes inside the quotation mark because the only part of the sentence that is a question is Where are the fish?
It helps to remember that the question mark stays attached to the question whether it is the whole sentence or just the quotation.
Indirect Questions Mixed with Direct Questions
It gets really crazy when you start mixing direct and indirect questions together. There are multiple ways to write something like The question at hand is, who stole the cookies? The simplest way to write that is to put a comma after the indirect question and a question mark after the direct question (4): The question at hand is, who stole the cookies?
Believe it or not, some style guides allow you to capitalize the first word in a direct question, even though it comes in the middle of a sentence: The question at hand is, Who stole the cookies? Supposedly, capitalizing the first word in the question places more emphasis on the question, but I think it makes the sentence look disjointed.
And if you think that looks weird, it gets even worse. If you flip the two parts around, you can put a question mark in the middle of your sentence (1, 3): Who stole the cookies? was the question at hand.
It's good to know the rules, but these sentences seem so contorted that I think it is better to try to rewrite them. I could easily convert the sentence to an indirect question: Everyone wondered who stole the cookies. Or I could use a colon to make the punctuation less odd: One question remained: Who stole the cookies?