question mark
The mark that ends a direct question.
A question mark ends a direct question, whether the question is a complete sentence or a fragment. It also ends a statement that a short tag turns into a question: The train leaves at noon, doesn’t it? A sentence that only reports a question is a statement and ends with a period. Each use of the question mark has its own entry, listed under Question Mark.
Examples
Use Where did you park? (The sentence asks a question directly.)
Use More coffee? (The fragment asks a question directly, so it takes a question mark.)
Use You locked the car, didn’t you? (The tag turns the statement into a question, so the sentence ends with a question mark.)
Use He asked where I had parked. (The sentence reports the question rather than asking it, so it ends with a period.)
Avoid He asked where I had parked? (The sentence asks nothing, so a question mark does not belong at the end.)