It's the first day of school, and the teacher announces to the class that they will learn to speak like grownups this year. To demonstrate, she asks the kids what they did this summer. The first child says, "I went on a choo-choo train ride."
"No," the teacher says, "you went on a train ride."
The second child says "I went on a tug-tug boat ride."
"No," the teacher says, "you went on a boat ride."
The third child says, full of pride, "I read a book." "Which one?" asks the teacher.