It's Tuesday today. The students are having Music class. It's their favourite subject. The Music teacher is Miss Zhao. She's great fun. She sings some relaxing songs with the students. Then she writes the word "smile" on the blackboard. She says, "This is one of the longest(最长的) words in English. "All the students laugh(笑) and a boy stands up and asks, "Why?" Miss Zhao says with a smile, "Because there is a mile (英里) in the word. "