Parenthetical elements can be enclosed in parentheses or set off by commas or long dashes with no space before or after the long dash. The use of dashes or parentheses is preferable if the parenthetical element contains commas. Note: To create a dash in typed material, use two hyphens with no space before or after, or insert an em dash as we have in the examples below.
Dashes emphasize the parenthetical element.
Three types of reports–”feasibility studies, proposals, and progress reports–will be studied in the next month.
Use a dash to add explanation or illustrate a point after an independent clause.
The candidate had all the necessary qualifications–adequate training, relevant experience, and excellent recommendations.