Is it proper to place a question mark after an em dash?
I have seen it both ways in books. Perhaps it is correct either way? Simply a matter of the author's style?
Example: "How do you know so—?"
Is it proper to place a question mark after an em dash?
I have seen it both ways in books. Perhaps it is correct either way? Simply a matter of the author's style?
Example: "How do you know so—?"
An em dash is often used to indicate that a speaker has been interrupted. A question mark is necessary to indicate that the speaker was asking a question. Therefore, the construction you quoted is created.
Do not use an em dash with a question mark unless it's for this purpose. (Beware that Tolkien's works use non-standard grammar regarding em dashes and question marks.)