An em dash can connect an independent clause with the related thought in sentences like, “Abby gave me a terrible haircut—and she expected a tip!” or “Evan wants me to apologize—but he didn’t even say he’s sorry!”
For example, you could say “I’d better have passed my test—it’s ninety percent of my class grade—or I’ll have to go to summer school. ” This use for the em dash is sometimes called the parenthetical dash, since the dash can take the place of parentheses.
An example of this is, “All of my school work—physics, Academic Decathlon, sociology, and calculus—got washed away when my house was flooded. ”
An example of this could include, “Of course, I’ll sign a prenuptial agreement—as long as it’s in my favor. ”
En dashes typically indicates an inclusive number sequence. Instructions to read pages 15-55, for example, indicates that all those pages should be read, not just page 15 and page 55. En dashes are also used to represent scores from contests and athletic events. For example, the Timberwolves beat the Bobcats 15-8 in last night’s game.
“The liberal-conservative debate” is an example of conflict. “A Boston-New York train ticket” is an example of connection. “The road runs east-west” is an example of direction.
This can work for longer phrases being used as compound adjectives, as well. “His spur-of-the-moment decision led him on a great adventure,” is one example.
An en dash (–) is most commonly used to indicate a range of numbers. An em dash (—) is most often used to indicate a break in thought or to set an appositive off from the rest of the sentence. Hyphens are used to connect two words into a single concept, such as with 2-liter bottle, or old-time traditions. Hyphens are half the length of a dash. Despite looking similar, they are actually not a dash at all.
“I love pizza. " “My mom makes me dinner. " “When you come over,” would be an example of a dependent clause. While it has both a subject and a verb, it does not represent a complete thought.
Remember that there are other useful punctuation marks including commas, semicolons, and parentheses.
