Neville was standing alone, halfway up the passage, staring at the stone wall opposite him with the same horrified, wide-eyed look he had worn when Moody had demonstrated the Cruciatus Curse.
To their surprise, Professor Moody had announced that he would be putting the Imperius Curse on each of them in turn, to demonstrate its power and to see whether they could resist its effects.
One Herbology lesson was enough to demonstrate this.
The Hogwarts staff, demonstrating a continued desire to impress the visitors from Beauxbatons and Durmstrang, seemed determined to show the castle at its best this Christmas.
I ask you to demonstrate your courage one more time.
Roun’ the middle," said Hagrid, demonstrating.
Merchieftainess Murcus has told us exactly what happened at the bottom of the lake, and we have therefore decided to award marks out of fifty for each of the champions, as follows…… "Fleur Delacour, though she demonstrated excellent use of the Bubble-Head Charm, was attacked by grindylows as she approached her goal, and failed to retrieve her hostage.
There are no more uses of "demonstrate" in the book.