Harry Potter and the Prisoner of Azkaban
"I mean, you're good Hermione, but no one's that good. How're you supposed to be in three classes at once?"
"Don't be silly," said Hermione shortly. "Of course I won't be in three classes at once." (6.1.20-1)
Then he stood up, stretched, and checked the time on the luminous alarm clock on his bedside table.
It was one o'clock in the morning. Harry's stomach gave a funny jolt. He had been thirteen years old, without realizing it, for a whole hour. (1.24-25)
"I reckon he's lost track of time, being on the run," said Ron. "Didn't realize it was Halloween. Otherwise he'd have come bursting in here." (9.1.12)