应答器（组）命名规则是什么？
参考答案：每个应答器（组）命名以B开头，后加公里标或信号机名称。（3分）其中公里标参照区间通过信号机命名规则执行。
根据句意，写出单词的正确形式。
1. Where (do) a bird live?
2. Giraffes (eat) leaves.
3. What (is) they doing?
4. Why is Tom (brush) his teeth?
5. The girls are (hug).
