密歇根新闻广播 英语中破折号的用法（在线收听）

How many dashes is too many? For some of you — especially those who are writers — that may be a rhetorical question.

For others, the dash is something of a mystery. You've seen it around, you know what it looks like, but you've never learned how to use it.

That may be because the dash — and keep in mind, we're talking about the em-dash — is kind of like the Wild West of punctuation marks.

It's extremely flexible and works in a lot of different situations.

In fact, it's almost easier to explain where you can't use a dash, but let's take a look at a few places where you can. 

For starters, if you're making a list or providing an explanation, you can use a dash in place of a colon:

"There are a variety of factors to consider when choosing a pet — size, cost, energy level and maintenance, to name a few." 

The dash can also be used to set off a parenthetical element. Of course, you could just use parentheses, but the dash can add emphasis. Check out this example from an article by our own Anne Curzan:

"How is ‘aren't I' more grammatical — or more logical for that matter — then ‘ain't I'?"

Dashes are also handy when you want to start a sentence with a list:

"The dirty dishes, the grungy carpet, the filthy bathroom — it was clear that housework wasn't his top priority."

Sometimes, other punctuation marks are technically correct, but just don't work as well as the dash. Here's a great example from George Eliot's "Middlemarch":

"He had done nothing exceptional in marrying — nothing but what society sanctions and considers an occasion for wreaths and bouquets."

Unfortunately, the versatility of the dash also makes it prone to overuse. One or two can add emphasis or clarity, but too many can disrupt the flow of your writing and make it confusing.