In speaking, we can pause, stop, or change our tone of voice. In writing, we use the following marks of punctuation to emphasize and clarify what we mean. Parentheses are occasionally and sparingly used for extra, nonessential material included in a sentence. For example, dates, sources, or ideas that are subordinate or tangential to the rest of the sentence are set apart in parentheses.
Parentheses always appear in pairs.
But comments set off with a pair of dashes appear less subordinate to the main sentence than do comments in parentheses. And material introduced after a single dash may be more emphatic and may serve a greater variety of rhetorical purposes than material introduced with a colon. Underlining and Italics Underlining and italics are not really punctuation, but they are significant textual effects used conventionally in a variety of situations. Before computerized word-processing was widely available, writers would underline certain terms in handwritten or manually typed pages, and the underlining would be replaced by italics in the published version. Since word processing today allows many options for font faces and textual effects, it is generally recommended that you choose either underlining or italics and use it consistently throughout a given document as needed.