"They have a classroom that is both large and beautiful."

或者

当描述"他们的教室又大又漂亮"时，可以通过以下方式来表达更多：

1. "Their classroom is not only spacious but also aesthetically pleasing."

2. "The classroom they have is both expansive and visually appealing."

（他们拥有的教室既宽敞又视觉上令人满意。）

3. "Their classroom is characterized by its generous size and attractive design."