If you want to be perceived of as a professional writer, one of these days (sooner, I hope, rather than later) you’ve got to learn (and teach) how to make a correct dash. There are two kinds of animals that look like dashes:
1) The em dash (so called because it’s the length of the small letter “m” in most typefaces)…used as you use it here—to separate parts of a sentence, or as casual punctuation; and
2) The hyphen (known to copy editors as the en dash, because it’s the width of the letter “n”). Used to separate compound words as in forty-seven, tightly-wrapped, etc.
When you confuse one with the other, you cause a nightmare for the copy editors who prepare a book for publication. Every single wrongly-made dash has to be fixed by hand.
So…here’s how to make the em dash on keyboards that don’t HAVE AN ACTUAL em dash (some few do):
Type two hyphens together, with NO space BEFORE, BETWEEN or AFTER them—like this, not like this- - or like this – or like this – etc.
The minute I see a manuscript where the dashes are made correctly, the minute I can concentrate on the message it contains instead of on its faulty messengering!