第110页 | 300 Days of Better Writing | 阅读 ‧ 电子书库

Day 113: Use the em dash for impact.

An em dash is the long dash (“—”). It is named em dash because it is about the width of the letter M, based on old typesetting standards.

The em dash has two uses:

To interject off-topic ideas into a sentence, andTo create impact by emphasizing some point.

The em dash creates a pause so that whatever follows it will be stressed. Consider this sentence.

“John is a great singer—at home.”

The em dash emphasizes the words “at home.” If we leave out the dash and write “John is a great singer at home,” we allow the reader to think that John is considered a great singer other places, too. With the dash, we make the point that John is not considered a great singer other places—only at home.

When you do this at the end of a sentence, you emphasize the importance of whatever follows the dash. Write a complete sentence before the dash, and then conclude with the impact statement after the dash.

Using two hyphens is acceptable in situations where the em dash cannot be displayed. For formal documents, use a regular em dash, not two hyphens.