Use a question mark [ ? ] at the end of a direct question. It is considered bad form to use a question mark in combination with other marks, although that is often done in informal prose in an attempt to convey complex tones: He told you what!? That combination (or similar combination) of punctuation marks is sometimes called an interrobang , but the interrobang currently has no role in academic prose.*

Be careful not to put a question mark at the end of an indirect question.

The instructor asked the students what they were doing.

I asked my sister if she had a date.

I wonder if Cheney will run for vice president again.

I wonder whether Cheney will run again.

Be careful to distinguish between an indirect question (above), and a question that is embedded within a statement which we do want to end with a question mark.

We can get to Boston quicker, can't we, if we take the interstate?

His question was, can we end this statement with a question mark?

She ended her remarks with a resounding why not?

I wonder: will Cheney run for office again?

Put a question mark at the end of a sentence that is, in fact, a direct question. (Sometimes writers will simply forget.) Rhetorical questions (asked when an answer is not really expected), by the way, are questions and deserve to end with a question mark:

How else should we end them, after all?

What if I said to you, "You've got a real problem here"? (Notice that the question mark here comes after the quotation mark and there is no period at the end of the statement.)

Sometimes a question will actually end with a series of brief questions. When that happens, especially when the brief questions are more or less follow-up questions to the main question, each of the little questions can begin with a lowercase letter and end with a question mark.

Who is responsible for executing the plan? the coach? the coaching staff? the players?

If a question mark is part of an italicized or underlined title, make sure that the question mark is also italicized:

My favorite book is Where Did He Go?

(Do not add a period after such a sentence that ends with the title's question mark. The question mark will also suffice to end the sentence.) If the question mark is not part of a sentence-ending title, don't italicize the question mark:

Did he sing the French national anthem, la Marseillaise?

When a question ends with an abbreviation, end the abbreviation with a period and then add the question mark.

Didn't he use to live in Washington, D.C.?

When a question constitutes a polite request, it is usually not followed by a question mark. This becomes more true as the request becomes longer and more complex: