Which sentence uses dashes incorrectly?
Most of her books—including the newest titles—are nonfiction.
Harry—along with his father—is always welcome at our house.
The dog wanted—to go outside—as soon as her owner got home from work.
She knew when it was time to wake up—7:00 a.m.—and did so before the alarm went off
The third one is incorrect! If you have other similar problems cover the dashes and the phrase inside to see if the sentence would make sense without it! :)