阅读短文。将句子补充完整，每根短横线上只填一个单词。

Last weekend, Lily visited her grandparents in Chengdu with her parents. They went there by train. Lily's grandpa is 75 years old. He was a teacher many years ago. He worked in a small school. There was only one small building on a hill at that time. There were no computers or internet. Now, the school has tall buildings and a computer room!