作业精灵老师示例：
Tina's friends come to see her. Tina shows them around her home. They go into the living room.
It's big and clean. They go into Tina's bedroom. It's small, but it's nice. They go into Bobby's bedroom.
They see a lot of books and toys on the floor. They cannot see Bobby. Where's Bobby? He's under the
bed. Bobby should put his books and toys in order.
