听力原文：

After the graduation ceremony, it was time to say goodbye, but none of the students wanted to leave. It is always hard to separate from the classmates and teachers when you have spent three years with each other. Some students were saying thanks to their teachers. Some were hugging with tears in the eyes. Some were taking photos together. Some of the teachers were talking with the students and told them that there would be lots of difficulties ahead of them. The teachers suggested the students be confident and responsible for themselves, and that they learn to deal with different types of difficulties. Many students were excited to set out on a new journey. They are thirsty for knowledge and look forward to entering senior high school, where they will be given wings to fly. 

Question: Why did none of the students want to leave after the graduation ceremony?

参考答案: 

Because it was hard for them to separate from their classmates and teachers.