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.*

A tag question is a device used to turn a statement into a question. It nearly always consists of a pronoun, a helping verb, and sometimes the word not. Although it begins as a statement, the tag question prevails when it comes to the end-mark: use a question mark. Notice that when the statement is positive, the tag question is expressed in the negative; when the statement is negative, the tag question is positive. (There are a few exceptions to this, frequently expressing an element of surprise or sarcasm: "So you've made your first million, have you?" "Oh, that's your plan, is it?") The following are more typical tag questions: